diff --git a/Makefile b/Makefile
index fff683f5aa..1742a68ade 100644
--- a/Makefile
+++ b/Makefile
@@ -22,6 +22,8 @@ CLOSURE_SOURCE_MAP=\
 		#--assume_function_wrapper\
 
 CLOSURE_FLAGS=\
+	        --js lib/closure-base.js\
+		--generate_exports\
 		--compilation_level ADVANCED_OPTIMIZATIONS\
 		--externs src/externs.js\
 		--warning_level VERBOSE\
diff --git a/lib/closure-base.js b/lib/closure-base.js
new file mode 100644
index 0000000000..bb232f8ac7
--- /dev/null
+++ b/lib/closure-base.js
@@ -0,0 +1,2547 @@
+// Copyright 2006 The Closure Library Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS-IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/**
+ * @fileoverview Bootstrap for the Google JS Library (Closure).
+ *
+ * In uncompiled mode base.js will write out Closure's deps file, unless the
+ * global <code>CLOSURE_NO_DEPS</code> is set to true.  This allows projects to
+ * include their own deps file(s) from different locations.
+ *
+ * @author arv@google.com (Erik Arvidsson)
+ *
+ * @provideGoog
+ */
+
+
+/**
+ * @define {boolean} Overridden to true by the compiler when --closure_pass
+ *     or --mark_as_compiled is specified.
+ */
+var COMPILED = false;
+
+
+/**
+ * Base namespace for the Closure library.  Checks to see goog is already
+ * defined in the current scope before assigning to prevent clobbering if
+ * base.js is loaded more than once.
+ *
+ * @const
+ */
+var goog = goog || {};
+
+
+/**
+ * Reference to the global context.  In most cases this will be 'window'.
+ */
+goog.global = this;
+
+
+/**
+ * A hook for overriding the define values in uncompiled mode.
+ *
+ * In uncompiled mode, {@code CLOSURE_UNCOMPILED_DEFINES} may be defined before
+ * loading base.js.  If a key is defined in {@code CLOSURE_UNCOMPILED_DEFINES},
+ * {@code goog.define} will use the value instead of the default value.  This
+ * allows flags to be overwritten without compilation (this is normally
+ * accomplished with the compiler's "define" flag).
+ *
+ * Example:
+ * <pre>
+ *   var CLOSURE_UNCOMPILED_DEFINES = {'goog.DEBUG': false};
+ * </pre>
+ *
+ * @type {Object<string, (string|number|boolean)>|undefined}
+ */
+goog.global.CLOSURE_UNCOMPILED_DEFINES;
+
+
+/**
+ * A hook for overriding the define values in uncompiled or compiled mode,
+ * like CLOSURE_UNCOMPILED_DEFINES but effective in compiled code.  In
+ * uncompiled code CLOSURE_UNCOMPILED_DEFINES takes precedence.
+ *
+ * Also unlike CLOSURE_UNCOMPILED_DEFINES the values must be number, boolean or
+ * string literals or the compiler will emit an error.
+ *
+ * While any @define value may be set, only those set with goog.define will be
+ * effective for uncompiled code.
+ *
+ * Example:
+ * <pre>
+ *   var CLOSURE_DEFINES = {'goog.DEBUG': false} ;
+ * </pre>
+ *
+ * @type {Object<string, (string|number|boolean)>|undefined}
+ */
+goog.global.CLOSURE_DEFINES;
+
+
+/**
+ * Returns true if the specified value is not undefined.
+ * WARNING: Do not use this to test if an object has a property. Use the in
+ * operator instead.
+ *
+ * @param {?} val Variable to test.
+ * @return {boolean} Whether variable is defined.
+ */
+goog.isDef = function(val) {
+  // void 0 always evaluates to undefined and hence we do not need to depend on
+  // the definition of the global variable named 'undefined'.
+  return val !== void 0;
+};
+
+
+/**
+ * Builds an object structure for the provided namespace path, ensuring that
+ * names that already exist are not overwritten. For example:
+ * "a.b.c" -> a = {};a.b={};a.b.c={};
+ * Used by goog.provide and goog.exportSymbol.
+ * @param {string} name name of the object that this file defines.
+ * @param {*=} opt_object the object to expose at the end of the path.
+ * @param {Object=} opt_objectToExportTo The object to add the path to; default
+ *     is |goog.global|.
+ * @private
+ */
+goog.exportPath_ = function(name, opt_object, opt_objectToExportTo) {
+  var parts = name.split('.');
+  var cur = opt_objectToExportTo || goog.global;
+
+  // Internet Explorer exhibits strange behavior when throwing errors from
+  // methods externed in this manner.  See the testExportSymbolExceptions in
+  // base_test.html for an example.
+  if (!(parts[0] in cur) && cur.execScript) {
+    cur.execScript('var ' + parts[0]);
+  }
+
+  // Certain browsers cannot parse code in the form for((a in b); c;);
+  // This pattern is produced by the JSCompiler when it collapses the
+  // statement above into the conditional loop below. To prevent this from
+  // happening, use a for-loop and reserve the init logic as below.
+
+  // Parentheses added to eliminate strict JS warning in Firefox.
+  for (var part; parts.length && (part = parts.shift());) {
+    if (!parts.length && goog.isDef(opt_object)) {
+      // last part and we have an object; use it
+      cur[part] = opt_object;
+    } else if (cur[part]) {
+      cur = cur[part];
+    } else {
+      cur = cur[part] = {};
+    }
+  }
+};
+
+
+/**
+ * Defines a named value. In uncompiled mode, the value is retrieved from
+ * CLOSURE_DEFINES or CLOSURE_UNCOMPILED_DEFINES if the object is defined and
+ * has the property specified, and otherwise used the defined defaultValue.
+ * When compiled the default can be overridden using the compiler
+ * options or the value set in the CLOSURE_DEFINES object.
+ *
+ * @param {string} name The distinguished name to provide.
+ * @param {string|number|boolean} defaultValue
+ */
+goog.define = function(name, defaultValue) {
+  var value = defaultValue;
+  if (!COMPILED) {
+    if (goog.global.CLOSURE_UNCOMPILED_DEFINES &&
+        Object.prototype.hasOwnProperty.call(
+            goog.global.CLOSURE_UNCOMPILED_DEFINES, name)) {
+      value = goog.global.CLOSURE_UNCOMPILED_DEFINES[name];
+    } else if (goog.global.CLOSURE_DEFINES &&
+        Object.prototype.hasOwnProperty.call(
+            goog.global.CLOSURE_DEFINES, name)) {
+      value = goog.global.CLOSURE_DEFINES[name];
+    }
+  }
+  goog.exportPath_(name, value);
+};
+
+
+/**
+ * @define {boolean} DEBUG is provided as a convenience so that debugging code
+ * that should not be included in a production js_binary can be easily stripped
+ * by specifying --define goog.DEBUG=false to the JSCompiler. For example, most
+ * toString() methods should be declared inside an "if (goog.DEBUG)" conditional
+ * because they are generally used for debugging purposes and it is difficult
+ * for the JSCompiler to statically determine whether they are used.
+ */
+goog.define('goog.DEBUG', true);
+
+
+/**
+ * @define {string} LOCALE defines the locale being used for compilation. It is
+ * used to select locale specific data to be compiled in js binary. BUILD rule
+ * can specify this value by "--define goog.LOCALE=<locale_name>" as JSCompiler
+ * option.
+ *
+ * Take into account that the locale code format is important. You should use
+ * the canonical Unicode format with hyphen as a delimiter. Language must be
+ * lowercase, Language Script - Capitalized, Region - UPPERCASE.
+ * There are few examples: pt-BR, en, en-US, sr-Latin-BO, zh-Hans-CN.
+ *
+ * See more info about locale codes here:
+ * http://www.unicode.org/reports/tr35/#Unicode_Language_and_Locale_Identifiers
+ *
+ * For language codes you should use values defined by ISO 693-1. See it here
+ * http://www.w3.org/WAI/ER/IG/ert/iso639.htm. There is only one exception from
+ * this rule: the Hebrew language. For legacy reasons the old code (iw) should
+ * be used instead of the new code (he), see http://wiki/Main/IIISynonyms.
+ */
+goog.define('goog.LOCALE', 'en');  // default to en
+
+
+/**
+ * @define {boolean} Whether this code is running on trusted sites.
+ *
+ * On untrusted sites, several native functions can be defined or overridden by
+ * external libraries like Prototype, Datejs, and JQuery and setting this flag
+ * to false forces closure to use its own implementations when possible.
+ *
+ * If your JavaScript can be loaded by a third party site and you are wary about
+ * relying on non-standard implementations, specify
+ * "--define goog.TRUSTED_SITE=false" to the JSCompiler.
+ */
+goog.define('goog.TRUSTED_SITE', true);
+
+
+/**
+ * @define {boolean} Whether a project is expected to be running in strict mode.
+ *
+ * This define can be used to trigger alternate implementations compatible with
+ * running in EcmaScript Strict mode or warn about unavailable functionality.
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions_and_function_scope/Strict_mode
+ *
+ */
+goog.define('goog.STRICT_MODE_COMPATIBLE', false);
+
+
+/**
+ * @define {boolean} Whether code that calls {@link goog.setTestOnly} should
+ *     be disallowed in the compilation unit.
+ */
+goog.define('goog.DISALLOW_TEST_ONLY_CODE', COMPILED && !goog.DEBUG);
+
+
+/**
+ * @define {boolean} Whether to use a Chrome app CSP-compliant method for
+ *     loading scripts via goog.require. @see appendScriptSrcNode_.
+ */
+goog.define('goog.ENABLE_CHROME_APP_SAFE_SCRIPT_LOADING', false);
+
+
+/**
+ * Defines a namespace in Closure.
+ *
+ * A namespace may only be defined once in a codebase. It may be defined using
+ * goog.provide() or goog.module().
+ *
+ * The presence of one or more goog.provide() calls in a file indicates
+ * that the file defines the given objects/namespaces.
+ * Provided symbols must not be null or undefined.
+ *
+ * In addition, goog.provide() creates the object stubs for a namespace
+ * (for example, goog.provide("goog.foo.bar") will create the object
+ * goog.foo.bar if it does not already exist).
+ *
+ * Build tools also scan for provide/require/module statements
+ * to discern dependencies, build dependency files (see deps.js), etc.
+ *
+ * @see goog.require
+ * @see goog.module
+ * @param {string} name Namespace provided by this file in the form
+ *     "goog.package.part".
+ */
+goog.provide = function(name) {
+  if (!COMPILED) {
+    // Ensure that the same namespace isn't provided twice.
+    // A goog.module/goog.provide maps a goog.require to a specific file
+    if (goog.isProvided_(name)) {
+      throw Error('Namespace "' + name + '" already declared.');
+    }
+  }
+
+  goog.constructNamespace_(name);
+};
+
+
+/**
+ * @param {string} name Namespace provided by this file in the form
+ *     "goog.package.part".
+ * @param {Object=} opt_obj The object to embed in the namespace.
+ * @private
+ */
+goog.constructNamespace_ = function(name, opt_obj) {
+  if (!COMPILED) {
+    delete goog.implicitNamespaces_[name];
+
+    var namespace = name;
+    while ((namespace = namespace.substring(0, namespace.lastIndexOf('.')))) {
+      if (goog.getObjectByName(namespace)) {
+        break;
+      }
+      goog.implicitNamespaces_[namespace] = true;
+    }
+  }
+
+  goog.exportPath_(name, opt_obj);
+};
+
+
+/**
+ * Module identifier validation regexp.
+ * Note: This is a conservative check, it is very possible to be more lenient,
+ *   the primary exclusion here is "/" and "\" and a leading ".", these
+ *   restrictions are intended to leave the door open for using goog.require
+ *   with relative file paths rather than module identifiers.
+ * @private
+ */
+goog.VALID_MODULE_RE_ = /^[a-zA-Z_$][a-zA-Z0-9._$]*$/;
+
+
+/**
+ * Defines a module in Closure.
+ *
+ * Marks that this file must be loaded as a module and claims the namespace.
+ *
+ * A namespace may only be defined once in a codebase. It may be defined using
+ * goog.provide() or goog.module().
+ *
+ * goog.module() has three requirements:
+ * - goog.module may not be used in the same file as goog.provide.
+ * - goog.module must be the first statement in the file.
+ * - only one goog.module is allowed per file.
+ *
+ * When a goog.module annotated file is loaded, it is enclosed in
+ * a strict function closure. This means that:
+ * - any variables declared in a goog.module file are private to the file
+ * (not global), though the compiler is expected to inline the module.
+ * - The code must obey all the rules of "strict" JavaScript.
+ * - the file will be marked as "use strict"
+ *
+ * NOTE: unlike goog.provide, goog.module does not declare any symbols by
+ * itself. If declared symbols are desired, use
+ * goog.module.declareLegacyNamespace().
+ *
+ *
+ * See the public goog.module proposal: http://goo.gl/Va1hin
+ *
+ * @param {string} name Namespace provided by this file in the form
+ *     "goog.package.part", is expected but not required.
+ */
+goog.module = function(name) {
+  if (!goog.isString(name) ||
+      !name ||
+      name.search(goog.VALID_MODULE_RE_) == -1) {
+    throw Error('Invalid module identifier');
+  }
+  if (!goog.isInModuleLoader_()) {
+    throw Error('Module ' + name + ' has been loaded incorrectly.');
+  }
+  if (goog.moduleLoaderState_.moduleName) {
+    throw Error('goog.module may only be called once per module.');
+  }
+
+  // Store the module name for the loader.
+  goog.moduleLoaderState_.moduleName = name;
+  if (!COMPILED) {
+    // Ensure that the same namespace isn't provided twice.
+    // A goog.module/goog.provide maps a goog.require to a specific file
+    if (goog.isProvided_(name)) {
+      throw Error('Namespace "' + name + '" already declared.');
+    }
+    delete goog.implicitNamespaces_[name];
+  }
+};
+
+
+/**
+ * @param {string} name The module identifier.
+ * @return {?} The module exports for an already loaded module or null.
+ *
+ * Note: This is not an alternative to goog.require, it does not
+ * indicate a hard dependency, instead it is used to indicate
+ * an optional dependency or to access the exports of a module
+ * that has already been loaded.
+ * @suppress {missingProvide}
+ */
+goog.module.get = function(name) {
+  return goog.module.getInternal_(name);
+};
+
+
+/**
+ * @param {string} name The module identifier.
+ * @return {?} The module exports for an already loaded module or null.
+ * @private
+ */
+goog.module.getInternal_ = function(name) {
+  if (!COMPILED) {
+    if (goog.isProvided_(name)) {
+      // goog.require only return a value with-in goog.module files.
+      return name in goog.loadedModules_ ?
+          goog.loadedModules_[name] :
+          goog.getObjectByName(name);
+    } else {
+      return null;
+    }
+  }
+};
+
+
+/**
+ * @private {?{
+ *   moduleName: (string|undefined),
+ *   declareTestMethods: boolean
+ * }}
+ */
+goog.moduleLoaderState_ = null;
+
+
+/**
+ * @private
+ * @return {boolean} Whether a goog.module is currently being initialized.
+ */
+goog.isInModuleLoader_ = function() {
+  return goog.moduleLoaderState_ != null;
+};
+
+
+/**
+ * Indicate that a module's exports that are known test methods should
+ * be copied to the global object.  This makes the test methods visible to
+ * test runners that inspect the global object.
+ *
+ * TODO(johnlenz): Make the test framework aware of goog.module so
+ * that this isn't necessary. Alternately combine this with goog.setTestOnly
+ * to minimize boiler plate.
+ * @suppress {missingProvide}
+ * @deprecated This approach does not translate to ES6 module syntax, instead
+ *    use goog.testing.testSuite to declare the test methods.
+ */
+goog.module.declareTestMethods = function() {
+  if (!goog.isInModuleLoader_()) {
+    throw new Error('goog.module.declareTestMethods must be called from ' +
+        'within a goog.module');
+  }
+  goog.moduleLoaderState_.declareTestMethods = true;
+};
+
+
+/**
+ * Provide the module's exports as a globally accessible object under the
+ * module's declared name.  This is intended to ease migration to goog.module
+ * for files that have existing usages.
+ * @suppress {missingProvide}
+ */
+goog.module.declareLegacyNamespace = function() {
+  if (!COMPILED && !goog.isInModuleLoader_()) {
+    throw new Error('goog.module.declareLegacyNamespace must be called from ' +
+        'within a goog.module');
+  }
+  if (!COMPILED && !goog.moduleLoaderState_.moduleName) {
+    throw Error('goog.module must be called prior to ' +
+        'goog.module.declareLegacyNamespace.');
+  }
+  goog.moduleLoaderState_.declareLegacyNamespace = true;
+};
+
+
+/**
+ * Marks that the current file should only be used for testing, and never for
+ * live code in production.
+ *
+ * In the case of unit tests, the message may optionally be an exact namespace
+ * for the test (e.g. 'goog.stringTest'). The linter will then ignore the extra
+ * provide (if not explicitly defined in the code).
+ *
+ * @param {string=} opt_message Optional message to add to the error that's
+ *     raised when used in production code.
+ */
+goog.setTestOnly = function(opt_message) {
+  if (goog.DISALLOW_TEST_ONLY_CODE) {
+    opt_message = opt_message || '';
+    throw Error('Importing test-only code into non-debug environment' +
+                (opt_message ? ': ' + opt_message : '.'));
+  }
+};
+
+
+/**
+ * Forward declares a symbol. This is an indication to the compiler that the
+ * symbol may be used in the source yet is not required and may not be provided
+ * in compilation.
+ *
+ * The most common usage of forward declaration is code that takes a type as a
+ * function parameter but does not need to require it. By forward declaring
+ * instead of requiring, no hard dependency is made, and (if not required
+ * elsewhere) the namespace may never be required and thus, not be pulled
+ * into the JavaScript binary. If it is required elsewhere, it will be type
+ * checked as normal.
+ *
+ *
+ * @param {string} name The namespace to forward declare in the form of
+ *     "goog.package.part".
+ */
+goog.forwardDeclare = function(name) {};
+
+
+if (!COMPILED) {
+
+  /**
+   * Check if the given name has been goog.provided. This will return false for
+   * names that are available only as implicit namespaces.
+   * @param {string} name name of the object to look for.
+   * @return {boolean} Whether the name has been provided.
+   * @private
+   */
+  goog.isProvided_ = function(name) {
+    return (name in goog.loadedModules_) ||
+        (!goog.implicitNamespaces_[name] &&
+            goog.isDefAndNotNull(goog.getObjectByName(name)));
+  };
+
+  /**
+   * Namespaces implicitly defined by goog.provide. For example,
+   * goog.provide('goog.events.Event') implicitly declares that 'goog' and
+   * 'goog.events' must be namespaces.
+   *
+   * @type {!Object<string, (boolean|undefined)>}
+   * @private
+   */
+  goog.implicitNamespaces_ = {'goog.module': true};
+
+  // NOTE: We add goog.module as an implicit namespace as goog.module is defined
+  // here and because the existing module package has not been moved yet out of
+  // the goog.module namespace. This satisifies both the debug loader and
+  // ahead-of-time dependency management.
+}
+
+
+/**
+ * Returns an object based on its fully qualified external name.  The object
+ * is not found if null or undefined.  If you are using a compilation pass that
+ * renames property names beware that using this function will not find renamed
+ * properties.
+ *
+ * @param {string} name The fully qualified name.
+ * @param {Object=} opt_obj The object within which to look; default is
+ *     |goog.global|.
+ * @return {?} The value (object or primitive) or, if not found, null.
+ */
+goog.getObjectByName = function(name, opt_obj) {
+  var parts = name.split('.');
+  var cur = opt_obj || goog.global;
+  for (var part; part = parts.shift(); ) {
+    if (goog.isDefAndNotNull(cur[part])) {
+      cur = cur[part];
+    } else {
+      return null;
+    }
+  }
+  return cur;
+};
+
+
+/**
+ * Globalizes a whole namespace, such as goog or goog.lang.
+ *
+ * @param {!Object} obj The namespace to globalize.
+ * @param {Object=} opt_global The object to add the properties to.
+ * @deprecated Properties may be explicitly exported to the global scope, but
+ *     this should no longer be done in bulk.
+ */
+goog.globalize = function(obj, opt_global) {
+  var global = opt_global || goog.global;
+  for (var x in obj) {
+    global[x] = obj[x];
+  }
+};
+
+
+/**
+ * Adds a dependency from a file to the files it requires.
+ * @param {string} relPath The path to the js file.
+ * @param {!Array<string>} provides An array of strings with
+ *     the names of the objects this file provides.
+ * @param {!Array<string>} requires An array of strings with
+ *     the names of the objects this file requires.
+ * @param {boolean=} opt_isModule Whether this dependency must be loaded as
+ *     a module as declared by goog.module.
+ */
+goog.addDependency = function(relPath, provides, requires, opt_isModule) {
+  if (goog.DEPENDENCIES_ENABLED) {
+    var provide, require;
+    var path = relPath.replace(/\\/g, '/');
+    var deps = goog.dependencies_;
+    for (var i = 0; provide = provides[i]; i++) {
+      deps.nameToPath[provide] = path;
+      deps.pathIsModule[path] = !!opt_isModule;
+    }
+    for (var j = 0; require = requires[j]; j++) {
+      if (!(path in deps.requires)) {
+        deps.requires[path] = {};
+      }
+      deps.requires[path][require] = true;
+    }
+  }
+};
+
+
+
+
+// NOTE(nnaze): The debug DOM loader was included in base.js as an original way
+// to do "debug-mode" development.  The dependency system can sometimes be
+// confusing, as can the debug DOM loader's asynchronous nature.
+//
+// With the DOM loader, a call to goog.require() is not blocking -- the script
+// will not load until some point after the current script.  If a namespace is
+// needed at runtime, it needs to be defined in a previous script, or loaded via
+// require() with its registered dependencies.
+// User-defined namespaces may need their own deps file.  See http://go/js_deps,
+// http://go/genjsdeps, or, externally, DepsWriter.
+// https://developers.google.com/closure/library/docs/depswriter
+//
+// Because of legacy clients, the DOM loader can't be easily removed from
+// base.js.  Work is being done to make it disableable or replaceable for
+// different environments (DOM-less JavaScript interpreters like Rhino or V8,
+// for example). See bootstrap/ for more information.
+
+
+/**
+ * @define {boolean} Whether to enable the debug loader.
+ *
+ * If enabled, a call to goog.require() will attempt to load the namespace by
+ * appending a script tag to the DOM (if the namespace has been registered).
+ *
+ * If disabled, goog.require() will simply assert that the namespace has been
+ * provided (and depend on the fact that some outside tool correctly ordered
+ * the script).
+ */
+goog.define('goog.ENABLE_DEBUG_LOADER', true);
+
+
+/**
+ * @param {string} msg
+ * @private
+ */
+goog.logToConsole_ = function(msg) {
+  if (goog.global.console) {
+    goog.global.console['error'](msg);
+  }
+};
+
+
+/**
+ * Implements a system for the dynamic resolution of dependencies that works in
+ * parallel with the BUILD system. Note that all calls to goog.require will be
+ * stripped by the JSCompiler when the --closure_pass option is used.
+ * @see goog.provide
+ * @param {string} name Namespace to include (as was given in goog.provide()) in
+ *     the form "goog.package.part".
+ * @return {?} If called within a goog.module file, the associated namespace or
+ *     module otherwise null.
+ */
+goog.require = function(name) {
+
+  // If the object already exists we do not need do do anything.
+  if (!COMPILED) {
+    if (goog.ENABLE_DEBUG_LOADER && goog.IS_OLD_IE_) {
+      goog.maybeProcessDeferredDep_(name);
+    }
+
+    if (goog.isProvided_(name)) {
+      if (goog.isInModuleLoader_()) {
+        return goog.module.getInternal_(name);
+      } else {
+        return null;
+      }
+    }
+
+    if (goog.ENABLE_DEBUG_LOADER) {
+      var path = goog.getPathFromDeps_(name);
+      if (path) {
+        goog.included_[path] = true;
+        goog.writeScripts_();
+        return null;
+      }
+    }
+
+    var errorMessage = 'goog.require could not find: ' + name;
+    goog.logToConsole_(errorMessage);
+
+    throw Error(errorMessage);
+  }
+};
+
+
+/**
+ * Path for included scripts.
+ * @type {string}
+ */
+goog.basePath = '';
+
+
+/**
+ * A hook for overriding the base path.
+ * @type {string|undefined}
+ */
+goog.global.CLOSURE_BASE_PATH;
+
+
+/**
+ * Whether to write out Closure's deps file. By default, the deps are written.
+ * @type {boolean|undefined}
+ */
+goog.global.CLOSURE_NO_DEPS;
+
+
+/**
+ * A function to import a single script. This is meant to be overridden when
+ * Closure is being run in non-HTML contexts, such as web workers. It's defined
+ * in the global scope so that it can be set before base.js is loaded, which
+ * allows deps.js to be imported properly.
+ *
+ * The function is passed the script source, which is a relative URI. It should
+ * return true if the script was imported, false otherwise.
+ * @type {(function(string): boolean)|undefined}
+ */
+goog.global.CLOSURE_IMPORT_SCRIPT;
+
+
+/**
+ * Null function used for default values of callbacks, etc.
+ * @return {void} Nothing.
+ */
+goog.nullFunction = function() {};
+
+
+
+/**
+ * When defining a class Foo with an abstract method bar(), you can do:
+ * Foo.prototype.bar = goog.abstractMethod
+ *
+ * Now if a subclass of Foo fails to override bar(), an error will be thrown
+ * when bar() is invoked.
+ *
+ * Note: This does not take the name of the function to override as an argument
+ * because that would make it more difficult to obfuscate our JavaScript code.
+ *
+ * @type {!Function}
+ * @throws {Error} when invoked to indicate the method should be overridden.
+ */
+goog.abstractMethod = function() {
+  throw Error('unimplemented abstract method');
+};
+
+
+/**
+ * Adds a {@code getInstance} static method that always returns the same
+ * instance object.
+ * @param {!Function} ctor The constructor for the class to add the static
+ *     method to.
+ */
+goog.addSingletonGetter = function(ctor) {
+  ctor.getInstance = function() {
+    if (ctor.instance_) {
+      return ctor.instance_;
+    }
+    if (goog.DEBUG) {
+      // NOTE: JSCompiler can't optimize away Array#push.
+      goog.instantiatedSingletons_[goog.instantiatedSingletons_.length] = ctor;
+    }
+    return ctor.instance_ = new ctor;
+  };
+};
+
+
+/**
+ * All singleton classes that have been instantiated, for testing. Don't read
+ * it directly, use the {@code goog.testing.singleton} module. The compiler
+ * removes this variable if unused.
+ * @type {!Array<!Function>}
+ * @private
+ */
+goog.instantiatedSingletons_ = [];
+
+
+/**
+ * @define {boolean} Whether to load goog.modules using {@code eval} when using
+ * the debug loader.  This provides a better debugging experience as the
+ * source is unmodified and can be edited using Chrome Workspaces or similar.
+ * However in some environments the use of {@code eval} is banned
+ * so we provide an alternative.
+ */
+goog.define('goog.LOAD_MODULE_USING_EVAL', true);
+
+
+/**
+ * @define {boolean} Whether the exports of goog.modules should be sealed when
+ * possible.
+ */
+goog.define('goog.SEAL_MODULE_EXPORTS', goog.DEBUG);
+
+
+/**
+ * The registry of initialized modules:
+ * the module identifier to module exports map.
+ * @private @const {!Object<string, ?>}
+ */
+goog.loadedModules_ = {};
+
+
+/**
+ * True if goog.dependencies_ is available.
+ * @const {boolean}
+ */
+goog.DEPENDENCIES_ENABLED = !COMPILED && goog.ENABLE_DEBUG_LOADER;
+
+
+if (goog.DEPENDENCIES_ENABLED) {
+  /**
+   * Object used to keep track of urls that have already been added. This record
+   * allows the prevention of circular dependencies.
+   * @private {!Object<string, boolean>}
+   */
+  goog.included_ = {};
+
+
+  /**
+   * This object is used to keep track of dependencies and other data that is
+   * used for loading scripts.
+   * @private
+   * @type {{
+   *   pathIsModule: !Object<string, boolean>,
+   *   nameToPath: !Object<string, string>,
+   *   requires: !Object<string, !Object<string, boolean>>,
+   *   visited: !Object<string, boolean>,
+   *   written: !Object<string, boolean>,
+   *   deferred: !Object<string, string>
+   * }}
+   */
+  goog.dependencies_ = {
+    pathIsModule: {}, // 1 to 1
+
+    nameToPath: {}, // 1 to 1
+
+    requires: {}, // 1 to many
+
+    // Used when resolving dependencies to prevent us from visiting file twice.
+    visited: {},
+
+    written: {}, // Used to keep track of script files we have written.
+
+    deferred: {} // Used to track deferred module evaluations in old IEs
+  };
+
+
+  /**
+   * Tries to detect whether is in the context of an HTML document.
+   * @return {boolean} True if it looks like HTML document.
+   * @private
+   */
+  goog.inHtmlDocument_ = function() {
+    var doc = goog.global.document;
+    return typeof doc != 'undefined' &&
+           'write' in doc;  // XULDocument misses write.
+  };
+
+
+  /**
+   * Tries to detect the base path of base.js script that bootstraps Closure.
+   * @private
+   */
+  goog.findBasePath_ = function() {
+    if (goog.global.CLOSURE_BASE_PATH) {
+      goog.basePath = goog.global.CLOSURE_BASE_PATH;
+      return;
+    } else if (!goog.inHtmlDocument_()) {
+      return;
+    }
+    var doc = goog.global.document;
+    var scripts = doc.getElementsByTagName('SCRIPT');
+    // Search backwards since the current script is in almost all cases the one
+    // that has base.js.
+    for (var i = scripts.length - 1; i >= 0; --i) {
+      var script = /** @type {!HTMLScriptElement} */ (scripts[i]);
+      var src = script.src;
+      var qmark = src.lastIndexOf('?');
+      var l = qmark == -1 ? src.length : qmark;
+      if (src.substr(l - 7, 7) == 'base.js') {
+        goog.basePath = src.substr(0, l - 7);
+        return;
+      }
+    }
+  };
+
+
+  /**
+   * Imports a script if, and only if, that script hasn't already been imported.
+   * (Must be called at execution time)
+   * @param {string} src Script source.
+   * @param {string=} opt_sourceText The optionally source text to evaluate
+   * @private
+   */
+  goog.importScript_ = function(src, opt_sourceText) {
+    var importScript = goog.global.CLOSURE_IMPORT_SCRIPT ||
+        goog.writeScriptTag_;
+    if (importScript(src, opt_sourceText)) {
+      goog.dependencies_.written[src] = true;
+    }
+  };
+
+
+  /** @const @private {boolean} */
+  goog.IS_OLD_IE_ = !goog.global.atob && goog.global.document &&
+      goog.global.document.all;
+
+
+  /**
+   * Given a URL initiate retrieval and execution of the module.
+   * @param {string} src Script source URL.
+   * @private
+   */
+  goog.importModule_ = function(src) {
+    // In an attempt to keep browsers from timing out loading scripts using
+    // synchronous XHRs, put each load in its own script block.
+    var bootstrap = 'goog.retrieveAndExecModule_("' + src + '");';
+
+    if (goog.importScript_('', bootstrap)) {
+      goog.dependencies_.written[src] = true;
+    }
+  };
+
+
+  /** @private {!Array<string>} */
+  goog.queuedModules_ = [];
+
+
+  /**
+   * Return an appropriate module text. Suitable to insert into
+   * a script tag (that is unescaped).
+   * @param {string} srcUrl
+   * @param {string} scriptText
+   * @return {string}
+   * @private
+   */
+  goog.wrapModule_ = function(srcUrl, scriptText) {
+    if (!goog.LOAD_MODULE_USING_EVAL || !goog.isDef(goog.global.JSON)) {
+      return '' +
+          'goog.loadModule(function(exports) {' +
+          '"use strict";' +
+          scriptText +
+          '\n' + // terminate any trailing single line comment.
+          ';return exports' +
+          '});' +
+          '\n//# sourceURL=' + srcUrl + '\n';
+    } else {
+      return '' +
+          'goog.loadModule(' +
+          goog.global.JSON.stringify(
+              scriptText + '\n//# sourceURL=' + srcUrl + '\n') +
+          ');';
+    }
+  };
+
+  // On IE9 and earlier, it is necessary to handle
+  // deferred module loads. In later browsers, the
+  // code to be evaluated is simply inserted as a script
+  // block in the correct order. To eval deferred
+  // code at the right time, we piggy back on goog.require to call
+  // goog.maybeProcessDeferredDep_.
+  //
+  // The goog.requires are used both to bootstrap
+  // the loading process (when no deps are available) and
+  // declare that they should be available.
+  //
+  // Here we eval the sources, if all the deps are available
+  // either already eval'd or goog.require'd.  This will
+  // be the case when all the dependencies have already
+  // been loaded, and the dependent module is loaded.
+  //
+  // But this alone isn't sufficient because it is also
+  // necessary to handle the case where there is no root
+  // that is not deferred.  For that there we register for an event
+  // and trigger goog.loadQueuedModules_ handle any remaining deferred
+  // evaluations.
+
+  /**
+   * Handle any remaining deferred goog.module evals.
+   * @private
+   */
+  goog.loadQueuedModules_ = function() {
+    var count = goog.queuedModules_.length;
+    if (count > 0) {
+      var queue = goog.queuedModules_;
+      goog.queuedModules_ = [];
+      for (var i = 0; i < count; i++) {
+        var path = queue[i];
+        goog.maybeProcessDeferredPath_(path);
+      }
+    }
+  };
+
+
+  /**
+   * Eval the named module if its dependencies are
+   * available.
+   * @param {string} name The module to load.
+   * @private
+   */
+  goog.maybeProcessDeferredDep_ = function(name) {
+    if (goog.isDeferredModule_(name) &&
+        goog.allDepsAreAvailable_(name)) {
+      var path = goog.getPathFromDeps_(name);
+      goog.maybeProcessDeferredPath_(goog.basePath + path);
+    }
+  };
+
+  /**
+   * @param {string} name The module to check.
+   * @return {boolean} Whether the name represents a
+   *     module whose evaluation has been deferred.
+   * @private
+   */
+  goog.isDeferredModule_ = function(name) {
+    var path = goog.getPathFromDeps_(name);
+    if (path && goog.dependencies_.pathIsModule[path]) {
+      var abspath = goog.basePath + path;
+      return (abspath) in goog.dependencies_.deferred;
+    }
+    return false;
+  };
+
+  /**
+   * @param {string} name The module to check.
+   * @return {boolean} Whether the name represents a
+   *     module whose declared dependencies have all been loaded
+   *     (eval'd or a deferred module load)
+   * @private
+   */
+  goog.allDepsAreAvailable_ = function(name) {
+    var path = goog.getPathFromDeps_(name);
+    if (path && (path in goog.dependencies_.requires)) {
+      for (var requireName in goog.dependencies_.requires[path]) {
+        if (!goog.isProvided_(requireName) &&
+            !goog.isDeferredModule_(requireName)) {
+          return false;
+        }
+      }
+    }
+    return true;
+  };
+
+
+  /**
+   * @param {string} abspath
+   * @private
+   */
+  goog.maybeProcessDeferredPath_ = function(abspath) {
+    if (abspath in goog.dependencies_.deferred) {
+      var src = goog.dependencies_.deferred[abspath];
+      delete goog.dependencies_.deferred[abspath];
+      goog.globalEval(src);
+    }
+  };
+
+
+  /**
+   * @param {function(?):?|string} moduleDef The module definition.
+   */
+  goog.loadModule = function(moduleDef) {
+    // NOTE: we allow function definitions to be either in the from
+    // of a string to eval (which keeps the original source intact) or
+    // in a eval forbidden environment (CSP) we allow a function definition
+    // which in its body must call {@code goog.module}, and return the exports
+    // of the module.
+    var previousState = goog.moduleLoaderState_;
+    try {
+      goog.moduleLoaderState_ = {
+        moduleName: undefined, declareTestMethods: false};
+      var exports;
+      if (goog.isFunction(moduleDef)) {
+        exports = moduleDef.call(goog.global, {});
+      } else if (goog.isString(moduleDef)) {
+        exports = goog.loadModuleFromSource_.call(goog.global, moduleDef);
+      } else {
+        throw Error('Invalid module definition');
+      }
+
+      var moduleName = goog.moduleLoaderState_.moduleName;
+      if (!goog.isString(moduleName) || !moduleName) {
+        throw Error('Invalid module name \"' + moduleName + '\"');
+      }
+
+      // Don't seal legacy namespaces as they may be uses as a parent of
+      // another namespace
+      if (goog.moduleLoaderState_.declareLegacyNamespace) {
+        goog.constructNamespace_(moduleName, exports);
+      } else if (goog.SEAL_MODULE_EXPORTS && Object.seal) {
+        Object.seal(exports);
+      }
+
+      goog.loadedModules_[moduleName] = exports;
+      if (goog.moduleLoaderState_.declareTestMethods) {
+        for (var entry in exports) {
+          if (entry.indexOf('test', 0) === 0 ||
+              entry == 'tearDown' ||
+              entry == 'setUp' ||
+              entry == 'setUpPage' ||
+              entry == 'tearDownPage') {
+            goog.global[entry] = exports[entry];
+          }
+        }
+      }
+    } finally {
+      goog.moduleLoaderState_ = previousState;
+    }
+  };
+
+
+  /**
+   * @param {string} source
+   * @return {!Object}
+   * @private
+   */
+  goog.loadModuleFromSource_ = function(source) {
+    // NOTE: we avoid declaring parameters or local variables here to avoid
+    // masking globals or leaking values into the module definition.
+    'use strict';
+    var exports = {};
+    eval(arguments[0]);
+    return exports;
+  };
+
+
+  /**
+   * Writes a new script pointing to {@code src} directly into the DOM.
+   *
+   * NOTE: This method is not CSP-compliant. @see goog.appendScriptSrcNode_ for
+   * the fallback mechanism.
+   *
+   * @param {string} src The script URL.
+   * @private
+   */
+  goog.writeScriptSrcNode_ = function(src) {
+    goog.global.document.write(
+        '<script type="text/javascript" src="' + src + '"></' + 'script>');
+  };
+
+
+  /**
+   * Appends a new script node to the DOM using a CSP-compliant mechanism. This
+   * method exists as a fallback for document.write (which is not allowed in a
+   * strict CSP context, e.g., Chrome apps).
+   *
+   * NOTE: This method is not analogous to using document.write to insert a
+   * <script> tag; specifically, the user agent will execute a script added by
+   * document.write immediately after the current script block finishes
+   * executing, whereas the DOM-appended script node will not be executed until
+   * the entire document is parsed and executed. That is to say, this script is
+   * added to the end of the script execution queue.
+   *
+   * The page must not attempt to call goog.required entities until after the
+   * document has loaded, e.g., in or after the window.onload callback.
+   *
+   * @param {string} src The script URL.
+   * @private
+   */
+  goog.appendScriptSrcNode_ = function(src) {
+    var doc = goog.global.document;
+    var scriptEl = doc.createElement('script');
+    scriptEl.type = 'text/javascript';
+    scriptEl.src = src;
+    scriptEl.defer = false;
+    scriptEl.async = false;
+    doc.head.appendChild(scriptEl);
+  };
+
+
+  /**
+   * The default implementation of the import function. Writes a script tag to
+   * import the script.
+   *
+   * @param {string} src The script url.
+   * @param {string=} opt_sourceText The optionally source text to evaluate
+   * @return {boolean} True if the script was imported, false otherwise.
+   * @private
+   */
+  goog.writeScriptTag_ = function(src, opt_sourceText) {
+    if (goog.inHtmlDocument_()) {
+      var doc = goog.global.document;
+
+      // If the user tries to require a new symbol after document load,
+      // something has gone terribly wrong. Doing a document.write would
+      // wipe out the page. This does not apply to the CSP-compliant method
+      // of writing script tags.
+      if (!goog.ENABLE_CHROME_APP_SAFE_SCRIPT_LOADING &&
+          doc.readyState == 'complete') {
+        // Certain test frameworks load base.js multiple times, which tries
+        // to write deps.js each time. If that happens, just fail silently.
+        // These frameworks wipe the page between each load of base.js, so this
+        // is OK.
+        var isDeps = /\bdeps.js$/.test(src);
+        if (isDeps) {
+          return false;
+        } else {
+          throw Error('Cannot write "' + src + '" after document load');
+        }
+      }
+
+      var isOldIE = goog.IS_OLD_IE_;
+
+      if (opt_sourceText === undefined) {
+        if (!isOldIE) {
+          if (goog.ENABLE_CHROME_APP_SAFE_SCRIPT_LOADING) {
+            goog.appendScriptSrcNode_(src);
+          } else {
+            goog.writeScriptSrcNode_(src);
+          }
+        } else {
+          var state = " onreadystatechange='goog.onScriptLoad_(this, " +
+              ++goog.lastNonModuleScriptIndex_ + ")' ";
+          doc.write(
+              '<script type="text/javascript" src="' +
+                  src + '"' + state + '></' + 'script>');
+        }
+      } else {
+        doc.write(
+            '<script type="text/javascript">' +
+            opt_sourceText +
+            '</' + 'script>');
+      }
+      return true;
+    } else {
+      return false;
+    }
+  };
+
+
+  /** @private {number} */
+  goog.lastNonModuleScriptIndex_ = 0;
+
+
+  /**
+   * A readystatechange handler for legacy IE
+   * @param {!HTMLScriptElement} script
+   * @param {number} scriptIndex
+   * @return {boolean}
+   * @private
+   */
+  goog.onScriptLoad_ = function(script, scriptIndex) {
+    // for now load the modules when we reach the last script,
+    // later allow more inter-mingling.
+    if (script.readyState == 'complete' &&
+        goog.lastNonModuleScriptIndex_ == scriptIndex) {
+      goog.loadQueuedModules_();
+    }
+    return true;
+  };
+
+  /**
+   * Resolves dependencies based on the dependencies added using addDependency
+   * and calls importScript_ in the correct order.
+   * @private
+   */
+  goog.writeScripts_ = function() {
+    /** @type {!Array<string>} The scripts we need to write this time. */
+    var scripts = [];
+    var seenScript = {};
+    var deps = goog.dependencies_;
+
+    /** @param {string} path */
+    function visitNode(path) {
+      if (path in deps.written) {
+        return;
+      }
+
+      // We have already visited this one. We can get here if we have cyclic
+      // dependencies.
+      if (path in deps.visited) {
+        if (!(path in seenScript)) {
+          seenScript[path] = true;
+          scripts.push(path);
+        }
+        return;
+      }
+
+      deps.visited[path] = true;
+
+      if (path in deps.requires) {
+        for (var requireName in deps.requires[path]) {
+          // If the required name is defined, we assume that it was already
+          // bootstrapped by other means.
+          if (!goog.isProvided_(requireName)) {
+            if (requireName in deps.nameToPath) {
+              visitNode(deps.nameToPath[requireName]);
+            } else {
+              throw Error('Undefined nameToPath for ' + requireName);
+            }
+          }
+        }
+      }
+
+      if (!(path in seenScript)) {
+        seenScript[path] = true;
+        scripts.push(path);
+      }
+    }
+
+    for (var path in goog.included_) {
+      if (!deps.written[path]) {
+        visitNode(path);
+      }
+    }
+
+    // record that we are going to load all these scripts.
+    for (var i = 0; i < scripts.length; i++) {
+      var path = scripts[i];
+      goog.dependencies_.written[path] = true;
+    }
+
+    // If a module is loaded synchronously then we need to
+    // clear the current inModuleLoader value, and restore it when we are
+    // done loading the current "requires".
+    var moduleState = goog.moduleLoaderState_;
+    goog.moduleLoaderState_ = null;
+
+    var loadingModule = false;
+    for (var i = 0; i < scripts.length; i++) {
+      var path = scripts[i];
+      if (path) {
+        if (!deps.pathIsModule[path]) {
+          goog.importScript_(goog.basePath + path);
+        } else {
+          loadingModule = true;
+          goog.importModule_(goog.basePath + path);
+        }
+      } else {
+        goog.moduleLoaderState_ = moduleState;
+        throw Error('Undefined script input');
+      }
+    }
+
+    // restore the current "module loading state"
+    goog.moduleLoaderState_ = moduleState;
+  };
+
+
+  /**
+   * Looks at the dependency rules and tries to determine the script file that
+   * fulfills a particular rule.
+   * @param {string} rule In the form goog.namespace.Class or project.script.
+   * @return {?string} Url corresponding to the rule, or null.
+   * @private
+   */
+  goog.getPathFromDeps_ = function(rule) {
+    if (rule in goog.dependencies_.nameToPath) {
+      return goog.dependencies_.nameToPath[rule];
+    } else {
+      return null;
+    }
+  };
+
+  goog.findBasePath_();
+
+  // Allow projects to manage the deps files themselves.
+  if (!goog.global.CLOSURE_NO_DEPS) {
+    goog.importScript_(goog.basePath + 'deps.js');
+  }
+}
+
+
+/**
+ * Normalize a file path by removing redundant ".." and extraneous "." file
+ * path components.
+ * @param {string} path
+ * @return {string}
+ * @private
+ */
+goog.normalizePath_ = function(path) {
+  var components = path.split('/');
+  var i = 0;
+  while (i < components.length) {
+    if (components[i] == '.') {
+      components.splice(i, 1);
+    } else if (i && components[i] == '..' &&
+        components[i - 1] && components[i - 1] != '..') {
+      components.splice(--i, 2);
+    } else {
+      i++;
+    }
+  }
+  return components.join('/');
+};
+
+
+/**
+ * Loads file by synchronous XHR. Should not be used in production environments.
+ * @param {string} src Source URL.
+ * @return {string} File contents.
+ * @private
+ */
+goog.loadFileSync_ = function(src) {
+  if (goog.global.CLOSURE_LOAD_FILE_SYNC) {
+    return goog.global.CLOSURE_LOAD_FILE_SYNC(src);
+  } else {
+    var xhr = new goog.global['XMLHttpRequest']();
+    xhr.open('get', src, false);
+    xhr.send();
+    return xhr.responseText;
+  }
+};
+
+
+/**
+ * Retrieve and execute a module.
+ * @param {string} src Script source URL.
+ * @private
+ */
+goog.retrieveAndExecModule_ = function(src) {
+  if (!COMPILED) {
+    // The full but non-canonicalized URL for later use.
+    var originalPath = src;
+    // Canonicalize the path, removing any /./ or /../ since Chrome's debugging
+    // console doesn't auto-canonicalize XHR loads as it does <script> srcs.
+    src = goog.normalizePath_(src);
+
+    var importScript = goog.global.CLOSURE_IMPORT_SCRIPT ||
+        goog.writeScriptTag_;
+
+    var scriptText = goog.loadFileSync_(src);
+
+    if (scriptText != null) {
+      var execModuleScript = goog.wrapModule_(src, scriptText);
+      var isOldIE = goog.IS_OLD_IE_;
+      if (isOldIE) {
+        goog.dependencies_.deferred[originalPath] = execModuleScript;
+        goog.queuedModules_.push(originalPath);
+      } else {
+        importScript(src, execModuleScript);
+      }
+    } else {
+      throw new Error('load of ' + src + 'failed');
+    }
+  }
+};
+
+
+//==============================================================================
+// Language Enhancements
+//==============================================================================
+
+
+/**
+ * This is a "fixed" version of the typeof operator.  It differs from the typeof
+ * operator in such a way that null returns 'null' and arrays return 'array'.
+ * @param {*} value The value to get the type of.
+ * @return {string} The name of the type.
+ */
+goog.typeOf = function(value) {
+  var s = typeof value;
+  if (s == 'object') {
+    if (value) {
+      // Check these first, so we can avoid calling Object.prototype.toString if
+      // possible.
+      //
+      // IE improperly marshals tyepof across execution contexts, but a
+      // cross-context object will still return false for "instanceof Object".
+      if (value instanceof Array) {
+        return 'array';
+      } else if (value instanceof Object) {
+        return s;
+      }
+
+      // HACK: In order to use an Object prototype method on the arbitrary
+      //   value, the compiler requires the value be cast to type Object,
+      //   even though the ECMA spec explicitly allows it.
+      var className = Object.prototype.toString.call(
+          /** @type {Object} */ (value));
+      // In Firefox 3.6, attempting to access iframe window objects' length
+      // property throws an NS_ERROR_FAILURE, so we need to special-case it
+      // here.
+      if (className == '[object Window]') {
+        return 'object';
+      }
+
+      // We cannot always use constructor == Array or instanceof Array because
+      // different frames have different Array objects. In IE6, if the iframe
+      // where the array was created is destroyed, the array loses its
+      // prototype. Then dereferencing val.splice here throws an exception, so
+      // we can't use goog.isFunction. Calling typeof directly returns 'unknown'
+      // so that will work. In this case, this function will return false and
+      // most array functions will still work because the array is still
+      // array-like (supports length and []) even though it has lost its
+      // prototype.
+      // Mark Miller noticed that Object.prototype.toString
+      // allows access to the unforgeable [[Class]] property.
+      //  15.2.4.2 Object.prototype.toString ( )
+      //  When the toString method is called, the following steps are taken:
+      //      1. Get the [[Class]] property of this object.
+      //      2. Compute a string value by concatenating the three strings
+      //         "[object ", Result(1), and "]".
+      //      3. Return Result(2).
+      // and this behavior survives the destruction of the execution context.
+      if ((className == '[object Array]' ||
+           // In IE all non value types are wrapped as objects across window
+           // boundaries (not iframe though) so we have to do object detection
+           // for this edge case.
+           typeof value.length == 'number' &&
+           typeof value.splice != 'undefined' &&
+           typeof value.propertyIsEnumerable != 'undefined' &&
+           !value.propertyIsEnumerable('splice')
+
+          )) {
+        return 'array';
+      }
+      // HACK: There is still an array case that fails.
+      //     function ArrayImpostor() {}
+      //     ArrayImpostor.prototype = [];
+      //     var impostor = new ArrayImpostor;
+      // this can be fixed by getting rid of the fast path
+      // (value instanceof Array) and solely relying on
+      // (value && Object.prototype.toString.vall(value) === '[object Array]')
+      // but that would require many more function calls and is not warranted
+      // unless closure code is receiving objects from untrusted sources.
+
+      // IE in cross-window calls does not correctly marshal the function type
+      // (it appears just as an object) so we cannot use just typeof val ==
+      // 'function'. However, if the object has a call property, it is a
+      // function.
+      if ((className == '[object Function]' ||
+          typeof value.call != 'undefined' &&
+          typeof value.propertyIsEnumerable != 'undefined' &&
+          !value.propertyIsEnumerable('call'))) {
+        return 'function';
+      }
+
+    } else {
+      return 'null';
+    }
+
+  } else if (s == 'function' && typeof value.call == 'undefined') {
+    // In Safari typeof nodeList returns 'function', and on Firefox typeof
+    // behaves similarly for HTML{Applet,Embed,Object}, Elements and RegExps. We
+    // would like to return object for those and we can detect an invalid
+    // function by making sure that the function object has a call method.
+    return 'object';
+  }
+  return s;
+};
+
+
+/**
+ * Returns true if the specified value is null.
+ * @param {?} val Variable to test.
+ * @return {boolean} Whether variable is null.
+ */
+goog.isNull = function(val) {
+  return val === null;
+};
+
+
+/**
+ * Returns true if the specified value is defined and not null.
+ * @param {?} val Variable to test.
+ * @return {boolean} Whether variable is defined and not null.
+ */
+goog.isDefAndNotNull = function(val) {
+  // Note that undefined == null.
+  return val != null;
+};
+
+
+/**
+ * Returns true if the specified value is an array.
+ * @param {?} val Variable to test.
+ * @return {boolean} Whether variable is an array.
+ */
+goog.isArray = function(val) {
+  return goog.typeOf(val) == 'array';
+};
+
+
+/**
+ * Returns true if the object looks like an array. To qualify as array like
+ * the value needs to be either a NodeList or an object with a Number length
+ * property. As a special case, a function value is not array like, because its
+ * length property is fixed to correspond to the number of expected arguments.
+ * @param {?} val Variable to test.
+ * @return {boolean} Whether variable is an array.
+ */
+goog.isArrayLike = function(val) {
+  var type = goog.typeOf(val);
+  // We do not use goog.isObject here in order to exclude function values.
+  return type == 'array' || type == 'object' && typeof val.length == 'number';
+};
+
+
+/**
+ * Returns true if the object looks like a Date. To qualify as Date-like the
+ * value needs to be an object and have a getFullYear() function.
+ * @param {?} val Variable to test.
+ * @return {boolean} Whether variable is a like a Date.
+ */
+goog.isDateLike = function(val) {
+  return goog.isObject(val) && typeof val.getFullYear == 'function';
+};
+
+
+/**
+ * Returns true if the specified value is a string.
+ * @param {?} val Variable to test.
+ * @return {boolean} Whether variable is a string.
+ */
+goog.isString = function(val) {
+  return typeof val == 'string';
+};
+
+
+/**
+ * Returns true if the specified value is a boolean.
+ * @param {?} val Variable to test.
+ * @return {boolean} Whether variable is boolean.
+ */
+goog.isBoolean = function(val) {
+  return typeof val == 'boolean';
+};
+
+
+/**
+ * Returns true if the specified value is a number.
+ * @param {?} val Variable to test.
+ * @return {boolean} Whether variable is a number.
+ */
+goog.isNumber = function(val) {
+  return typeof val == 'number';
+};
+
+
+/**
+ * Returns true if the specified value is a function.
+ * @param {?} val Variable to test.
+ * @return {boolean} Whether variable is a function.
+ */
+goog.isFunction = function(val) {
+  return goog.typeOf(val) == 'function';
+};
+
+
+/**
+ * Returns true if the specified value is an object.  This includes arrays and
+ * functions.
+ * @param {?} val Variable to test.
+ * @return {boolean} Whether variable is an object.
+ */
+goog.isObject = function(val) {
+  var type = typeof val;
+  return type == 'object' && val != null || type == 'function';
+  // return Object(val) === val also works, but is slower, especially if val is
+  // not an object.
+};
+
+
+/**
+ * Gets a unique ID for an object. This mutates the object so that further calls
+ * with the same object as a parameter returns the same value. The unique ID is
+ * guaranteed to be unique across the current session amongst objects that are
+ * passed into {@code getUid}. There is no guarantee that the ID is unique or
+ * consistent across sessions. It is unsafe to generate unique ID for function
+ * prototypes.
+ *
+ * @param {Object} obj The object to get the unique ID for.
+ * @return {number} The unique ID for the object.
+ */
+goog.getUid = function(obj) {
+  // TODO(arv): Make the type stricter, do not accept null.
+
+  // In Opera window.hasOwnProperty exists but always returns false so we avoid
+  // using it. As a consequence the unique ID generated for BaseClass.prototype
+  // and SubClass.prototype will be the same.
+  return obj[goog.UID_PROPERTY_] ||
+      (obj[goog.UID_PROPERTY_] = ++goog.uidCounter_);
+};
+
+
+/**
+ * Whether the given object is already assigned a unique ID.
+ *
+ * This does not modify the object.
+ *
+ * @param {!Object} obj The object to check.
+ * @return {boolean} Whether there is an assigned unique id for the object.
+ */
+goog.hasUid = function(obj) {
+  return !!obj[goog.UID_PROPERTY_];
+};
+
+
+/**
+ * Removes the unique ID from an object. This is useful if the object was
+ * previously mutated using {@code goog.getUid} in which case the mutation is
+ * undone.
+ * @param {Object} obj The object to remove the unique ID field from.
+ */
+goog.removeUid = function(obj) {
+  // TODO(arv): Make the type stricter, do not accept null.
+
+  // In IE, DOM nodes are not instances of Object and throw an exception if we
+  // try to delete.  Instead we try to use removeAttribute.
+  if ('removeAttribute' in obj) {
+    obj.removeAttribute(goog.UID_PROPERTY_);
+  }
+  /** @preserveTry */
+  try {
+    delete obj[goog.UID_PROPERTY_];
+  } catch (ex) {
+  }
+};
+
+
+/**
+ * Name for unique ID property. Initialized in a way to help avoid collisions
+ * with other closure JavaScript on the same page.
+ * @type {string}
+ * @private
+ */
+goog.UID_PROPERTY_ = 'closure_uid_' + ((Math.random() * 1e9) >>> 0);
+
+
+/**
+ * Counter for UID.
+ * @type {number}
+ * @private
+ */
+goog.uidCounter_ = 0;
+
+
+/**
+ * Adds a hash code field to an object. The hash code is unique for the
+ * given object.
+ * @param {Object} obj The object to get the hash code for.
+ * @return {number} The hash code for the object.
+ * @deprecated Use goog.getUid instead.
+ */
+goog.getHashCode = goog.getUid;
+
+
+/**
+ * Removes the hash code field from an object.
+ * @param {Object} obj The object to remove the field from.
+ * @deprecated Use goog.removeUid instead.
+ */
+goog.removeHashCode = goog.removeUid;
+
+
+/**
+ * Clones a value. The input may be an Object, Array, or basic type. Objects and
+ * arrays will be cloned recursively.
+ *
+ * WARNINGS:
+ * <code>goog.cloneObject</code> does not detect reference loops. Objects that
+ * refer to themselves will cause infinite recursion.
+ *
+ * <code>goog.cloneObject</code> is unaware of unique identifiers, and copies
+ * UIDs created by <code>getUid</code> into cloned results.
+ *
+ * @param {*} obj The value to clone.
+ * @return {*} A clone of the input value.
+ * @deprecated goog.cloneObject is unsafe. Prefer the goog.object methods.
+ */
+goog.cloneObject = function(obj) {
+  var type = goog.typeOf(obj);
+  if (type == 'object' || type == 'array') {
+    if (obj.clone) {
+      return obj.clone();
+    }
+    var clone = type == 'array' ? [] : {};
+    for (var key in obj) {
+      clone[key] = goog.cloneObject(obj[key]);
+    }
+    return clone;
+  }
+
+  return obj;
+};
+
+
+/**
+ * A native implementation of goog.bind.
+ * @param {Function} fn A function to partially apply.
+ * @param {Object|undefined} selfObj Specifies the object which this should
+ *     point to when the function is run.
+ * @param {...*} var_args Additional arguments that are partially applied to the
+ *     function.
+ * @return {!Function} A partially-applied form of the function bind() was
+ *     invoked as a method of.
+ * @private
+ * @suppress {deprecated} The compiler thinks that Function.prototype.bind is
+ *     deprecated because some people have declared a pure-JS version.
+ *     Only the pure-JS version is truly deprecated.
+ */
+goog.bindNative_ = function(fn, selfObj, var_args) {
+  return /** @type {!Function} */ (fn.call.apply(fn.bind, arguments));
+};
+
+
+/**
+ * A pure-JS implementation of goog.bind.
+ * @param {Function} fn A function to partially apply.
+ * @param {Object|undefined} selfObj Specifies the object which this should
+ *     point to when the function is run.
+ * @param {...*} var_args Additional arguments that are partially applied to the
+ *     function.
+ * @return {!Function} A partially-applied form of the function bind() was
+ *     invoked as a method of.
+ * @private
+ */
+goog.bindJs_ = function(fn, selfObj, var_args) {
+  if (!fn) {
+    throw new Error();
+  }
+
+  if (arguments.length > 2) {
+    var boundArgs = Array.prototype.slice.call(arguments, 2);
+    return function() {
+      // Prepend the bound arguments to the current arguments.
+      var newArgs = Array.prototype.slice.call(arguments);
+      Array.prototype.unshift.apply(newArgs, boundArgs);
+      return fn.apply(selfObj, newArgs);
+    };
+
+  } else {
+    return function() {
+      return fn.apply(selfObj, arguments);
+    };
+  }
+};
+
+
+/**
+ * Partially applies this function to a particular 'this object' and zero or
+ * more arguments. The result is a new function with some arguments of the first
+ * function pre-filled and the value of this 'pre-specified'.
+ *
+ * Remaining arguments specified at call-time are appended to the pre-specified
+ * ones.
+ *
+ * Also see: {@link #partial}.
+ *
+ * Usage:
+ * <pre>var barMethBound = bind(myFunction, myObj, 'arg1', 'arg2');
+ * barMethBound('arg3', 'arg4');</pre>
+ *
+ * @param {?function(this:T, ...)} fn A function to partially apply.
+ * @param {T} selfObj Specifies the object which this should point to when the
+ *     function is run.
+ * @param {...*} var_args Additional arguments that are partially applied to the
+ *     function.
+ * @return {!Function} A partially-applied form of the function bind() was
+ *     invoked as a method of.
+ * @template T
+ * @suppress {deprecated} See above.
+ */
+goog.bind = function(fn, selfObj, var_args) {
+  // TODO(nicksantos): narrow the type signature.
+  if (Function.prototype.bind &&
+      // NOTE(nicksantos): Somebody pulled base.js into the default Chrome
+      // extension environment. This means that for Chrome extensions, they get
+      // the implementation of Function.prototype.bind that calls goog.bind
+      // instead of the native one. Even worse, we don't want to introduce a
+      // circular dependency between goog.bind and Function.prototype.bind, so
+      // we have to hack this to make sure it works correctly.
+      Function.prototype.bind.toString().indexOf('native code') != -1) {
+    goog.bind = goog.bindNative_;
+  } else {
+    goog.bind = goog.bindJs_;
+  }
+  return goog.bind.apply(null, arguments);
+};
+
+
+/**
+ * Like bind(), except that a 'this object' is not required. Useful when the
+ * target function is already bound.
+ *
+ * Usage:
+ * var g = partial(f, arg1, arg2);
+ * g(arg3, arg4);
+ *
+ * @param {Function} fn A function to partially apply.
+ * @param {...*} var_args Additional arguments that are partially applied to fn.
+ * @return {!Function} A partially-applied form of the function bind() was
+ *     invoked as a method of.
+ */
+goog.partial = function(fn, var_args) {
+  var args = Array.prototype.slice.call(arguments, 1);
+  return function() {
+    // Clone the array (with slice()) and append additional arguments
+    // to the existing arguments.
+    var newArgs = args.slice();
+    newArgs.push.apply(newArgs, arguments);
+    return fn.apply(this, newArgs);
+  };
+};
+
+
+/**
+ * Copies all the members of a source object to a target object. This method
+ * does not work on all browsers for all objects that contain keys such as
+ * toString or hasOwnProperty. Use goog.object.extend for this purpose.
+ * @param {Object} target Target.
+ * @param {Object} source Source.
+ */
+goog.mixin = function(target, source) {
+  for (var x in source) {
+    target[x] = source[x];
+  }
+
+  // For IE7 or lower, the for-in-loop does not contain any properties that are
+  // not enumerable on the prototype object (for example, isPrototypeOf from
+  // Object.prototype) but also it will not include 'replace' on objects that
+  // extend String and change 'replace' (not that it is common for anyone to
+  // extend anything except Object).
+};
+
+
+/**
+ * @return {number} An integer value representing the number of milliseconds
+ *     between midnight, January 1, 1970 and the current time.
+ */
+goog.now = (goog.TRUSTED_SITE && Date.now) || (function() {
+  // Unary plus operator converts its operand to a number which in the case of
+  // a date is done by calling getTime().
+  return +new Date();
+});
+
+
+/**
+ * Evals JavaScript in the global scope.  In IE this uses execScript, other
+ * browsers use goog.global.eval. If goog.global.eval does not evaluate in the
+ * global scope (for example, in Safari), appends a script tag instead.
+ * Throws an exception if neither execScript or eval is defined.
+ * @param {string} script JavaScript string.
+ */
+goog.globalEval = function(script) {
+  if (goog.global.execScript) {
+    goog.global.execScript(script, 'JavaScript');
+  } else if (goog.global.eval) {
+    // Test to see if eval works
+    if (goog.evalWorksForGlobals_ == null) {
+      goog.global.eval('var _et_ = 1;');
+      if (typeof goog.global['_et_'] != 'undefined') {
+        delete goog.global['_et_'];
+        goog.evalWorksForGlobals_ = true;
+      } else {
+        goog.evalWorksForGlobals_ = false;
+      }
+    }
+
+    if (goog.evalWorksForGlobals_) {
+      goog.global.eval(script);
+    } else {
+      var doc = goog.global.document;
+      var scriptElt = doc.createElement('SCRIPT');
+      scriptElt.type = 'text/javascript';
+      scriptElt.defer = false;
+      // Note(user): can't use .innerHTML since "t('<test>')" will fail and
+      // .text doesn't work in Safari 2.  Therefore we append a text node.
+      scriptElt.appendChild(doc.createTextNode(script));
+      doc.body.appendChild(scriptElt);
+      doc.body.removeChild(scriptElt);
+    }
+  } else {
+    throw Error('goog.globalEval not available');
+  }
+};
+
+
+/**
+ * Indicates whether or not we can call 'eval' directly to eval code in the
+ * global scope. Set to a Boolean by the first call to goog.globalEval (which
+ * empirically tests whether eval works for globals). @see goog.globalEval
+ * @type {?boolean}
+ * @private
+ */
+goog.evalWorksForGlobals_ = null;
+
+
+/**
+ * Optional map of CSS class names to obfuscated names used with
+ * goog.getCssName().
+ * @private {!Object<string, string>|undefined}
+ * @see goog.setCssNameMapping
+ */
+goog.cssNameMapping_;
+
+
+/**
+ * Optional obfuscation style for CSS class names. Should be set to either
+ * 'BY_WHOLE' or 'BY_PART' if defined.
+ * @type {string|undefined}
+ * @private
+ * @see goog.setCssNameMapping
+ */
+goog.cssNameMappingStyle_;
+
+
+/**
+ * Handles strings that are intended to be used as CSS class names.
+ *
+ * This function works in tandem with @see goog.setCssNameMapping.
+ *
+ * Without any mapping set, the arguments are simple joined with a hyphen and
+ * passed through unaltered.
+ *
+ * When there is a mapping, there are two possible styles in which these
+ * mappings are used. In the BY_PART style, each part (i.e. in between hyphens)
+ * of the passed in css name is rewritten according to the map. In the BY_WHOLE
+ * style, the full css name is looked up in the map directly. If a rewrite is
+ * not specified by the map, the compiler will output a warning.
+ *
+ * When the mapping is passed to the compiler, it will replace calls to
+ * goog.getCssName with the strings from the mapping, e.g.
+ *     var x = goog.getCssName('foo');
+ *     var y = goog.getCssName(this.baseClass, 'active');
+ *  becomes:
+ *     var x= 'foo';
+ *     var y = this.baseClass + '-active';
+ *
+ * If one argument is passed it will be processed, if two are passed only the
+ * modifier will be processed, as it is assumed the first argument was generated
+ * as a result of calling goog.getCssName.
+ *
+ * @param {string} className The class name.
+ * @param {string=} opt_modifier A modifier to be appended to the class name.
+ * @return {string} The class name or the concatenation of the class name and
+ *     the modifier.
+ */
+goog.getCssName = function(className, opt_modifier) {
+  var getMapping = function(cssName) {
+    return goog.cssNameMapping_[cssName] || cssName;
+  };
+
+  var renameByParts = function(cssName) {
+    // Remap all the parts individually.
+    var parts = cssName.split('-');
+    var mapped = [];
+    for (var i = 0; i < parts.length; i++) {
+      mapped.push(getMapping(parts[i]));
+    }
+    return mapped.join('-');
+  };
+
+  var rename;
+  if (goog.cssNameMapping_) {
+    rename = goog.cssNameMappingStyle_ == 'BY_WHOLE' ?
+        getMapping : renameByParts;
+  } else {
+    rename = function(a) {
+      return a;
+    };
+  }
+
+  if (opt_modifier) {
+    return className + '-' + rename(opt_modifier);
+  } else {
+    return rename(className);
+  }
+};
+
+
+/**
+ * Sets the map to check when returning a value from goog.getCssName(). Example:
+ * <pre>
+ * goog.setCssNameMapping({
+ *   "goog": "a",
+ *   "disabled": "b",
+ * });
+ *
+ * var x = goog.getCssName('goog');
+ * // The following evaluates to: "a a-b".
+ * goog.getCssName('goog') + ' ' + goog.getCssName(x, 'disabled')
+ * </pre>
+ * When declared as a map of string literals to string literals, the JSCompiler
+ * will replace all calls to goog.getCssName() using the supplied map if the
+ * --closure_pass flag is set.
+ *
+ * @param {!Object} mapping A map of strings to strings where keys are possible
+ *     arguments to goog.getCssName() and values are the corresponding values
+ *     that should be returned.
+ * @param {string=} opt_style The style of css name mapping. There are two valid
+ *     options: 'BY_PART', and 'BY_WHOLE'.
+ * @see goog.getCssName for a description.
+ */
+goog.setCssNameMapping = function(mapping, opt_style) {
+  goog.cssNameMapping_ = mapping;
+  goog.cssNameMappingStyle_ = opt_style;
+};
+
+
+/**
+ * To use CSS renaming in compiled mode, one of the input files should have a
+ * call to goog.setCssNameMapping() with an object literal that the JSCompiler
+ * can extract and use to replace all calls to goog.getCssName(). In uncompiled
+ * mode, JavaScript code should be loaded before this base.js file that declares
+ * a global variable, CLOSURE_CSS_NAME_MAPPING, which is used below. This is
+ * to ensure that the mapping is loaded before any calls to goog.getCssName()
+ * are made in uncompiled mode.
+ *
+ * A hook for overriding the CSS name mapping.
+ * @type {!Object<string, string>|undefined}
+ */
+goog.global.CLOSURE_CSS_NAME_MAPPING;
+
+
+if (!COMPILED && goog.global.CLOSURE_CSS_NAME_MAPPING) {
+  // This does not call goog.setCssNameMapping() because the JSCompiler
+  // requires that goog.setCssNameMapping() be called with an object literal.
+  goog.cssNameMapping_ = goog.global.CLOSURE_CSS_NAME_MAPPING;
+}
+
+
+/**
+ * Gets a localized message.
+ *
+ * This function is a compiler primitive. If you give the compiler a localized
+ * message bundle, it will replace the string at compile-time with a localized
+ * version, and expand goog.getMsg call to a concatenated string.
+ *
+ * Messages must be initialized in the form:
+ * <code>
+ * var MSG_NAME = goog.getMsg('Hello {$placeholder}', {'placeholder': 'world'});
+ * </code>
+ *
+ * @param {string} str Translatable string, places holders in the form {$foo}.
+ * @param {Object<string, string>=} opt_values Maps place holder name to value.
+ * @return {string} message with placeholders filled.
+ */
+goog.getMsg = function(str, opt_values) {
+  if (opt_values) {
+    str = str.replace(/\{\$([^}]+)}/g, function(match, key) {
+      return key in opt_values ? opt_values[key] : match;
+    });
+  }
+  return str;
+};
+
+
+/**
+ * Gets a localized message. If the message does not have a translation, gives a
+ * fallback message.
+ *
+ * This is useful when introducing a new message that has not yet been
+ * translated into all languages.
+ *
+ * This function is a compiler primitive. Must be used in the form:
+ * <code>var x = goog.getMsgWithFallback(MSG_A, MSG_B);</code>
+ * where MSG_A and MSG_B were initialized with goog.getMsg.
+ *
+ * @param {string} a The preferred message.
+ * @param {string} b The fallback message.
+ * @return {string} The best translated message.
+ */
+goog.getMsgWithFallback = function(a, b) {
+  return a;
+};
+
+
+/**
+ * Exposes an unobfuscated global namespace path for the given object.
+ * Note that fields of the exported object *will* be obfuscated, unless they are
+ * exported in turn via this function or goog.exportProperty.
+ *
+ * Also handy for making public items that are defined in anonymous closures.
+ *
+ * ex. goog.exportSymbol('public.path.Foo', Foo);
+ *
+ * ex. goog.exportSymbol('public.path.Foo.staticFunction', Foo.staticFunction);
+ *     public.path.Foo.staticFunction();
+ *
+ * ex. goog.exportSymbol('public.path.Foo.prototype.myMethod',
+ *                       Foo.prototype.myMethod);
+ *     new public.path.Foo().myMethod();
+ *
+ * @param {string} publicPath Unobfuscated name to export.
+ * @param {*} object Object the name should point to.
+ * @param {Object=} opt_objectToExportTo The object to add the path to; default
+ *     is goog.global.
+ */
+goog.exportSymbol = function(publicPath, object, opt_objectToExportTo) {
+  goog.exportPath_(publicPath, object, opt_objectToExportTo);
+};
+
+
+/**
+ * Exports a property unobfuscated into the object's namespace.
+ * ex. goog.exportProperty(Foo, 'staticFunction', Foo.staticFunction);
+ * ex. goog.exportProperty(Foo.prototype, 'myMethod', Foo.prototype.myMethod);
+ * @param {Object} object Object whose static property is being exported.
+ * @param {string} publicName Unobfuscated name to export.
+ * @param {*} symbol Object the name should point to.
+ */
+goog.exportProperty = function(object, publicName, symbol) {
+  object[publicName] = symbol;
+};
+
+
+/**
+ * Inherit the prototype methods from one constructor into another.
+ *
+ * Usage:
+ * <pre>
+ * function ParentClass(a, b) { }
+ * ParentClass.prototype.foo = function(a) { };
+ *
+ * function ChildClass(a, b, c) {
+ *   ChildClass.base(this, 'constructor', a, b);
+ * }
+ * goog.inherits(ChildClass, ParentClass);
+ *
+ * var child = new ChildClass('a', 'b', 'see');
+ * child.foo(); // This works.
+ * </pre>
+ *
+ * @param {Function} childCtor Child class.
+ * @param {Function} parentCtor Parent class.
+ */
+goog.inherits = function(childCtor, parentCtor) {
+  /** @constructor */
+  function tempCtor() {};
+  tempCtor.prototype = parentCtor.prototype;
+  childCtor.superClass_ = parentCtor.prototype;
+  childCtor.prototype = new tempCtor();
+  /** @override */
+  childCtor.prototype.constructor = childCtor;
+
+  /**
+   * Calls superclass constructor/method.
+   *
+   * This function is only available if you use goog.inherits to
+   * express inheritance relationships between classes.
+   *
+   * NOTE: This is a replacement for goog.base and for superClass_
+   * property defined in childCtor.
+   *
+   * @param {!Object} me Should always be "this".
+   * @param {string} methodName The method name to call. Calling
+   *     superclass constructor can be done with the special string
+   *     'constructor'.
+   * @param {...*} var_args The arguments to pass to superclass
+   *     method/constructor.
+   * @return {*} The return value of the superclass method/constructor.
+   */
+  childCtor.base = function(me, methodName, var_args) {
+    // Copying using loop to avoid deop due to passing arguments object to
+    // function. This is faster in many JS engines as of late 2014.
+    var args = new Array(arguments.length - 2);
+    for (var i = 2; i < arguments.length; i++) {
+      args[i - 2] = arguments[i];
+    }
+    return parentCtor.prototype[methodName].apply(me, args);
+  };
+};
+
+
+/**
+ * Call up to the superclass.
+ *
+ * If this is called from a constructor, then this calls the superclass
+ * constructor with arguments 1-N.
+ *
+ * If this is called from a prototype method, then you must pass the name of the
+ * method as the second argument to this function. If you do not, you will get a
+ * runtime error. This calls the superclass' method with arguments 2-N.
+ *
+ * This function only works if you use goog.inherits to express inheritance
+ * relationships between your classes.
+ *
+ * This function is a compiler primitive. At compile-time, the compiler will do
+ * macro expansion to remove a lot of the extra overhead that this function
+ * introduces. The compiler will also enforce a lot of the assumptions that this
+ * function makes, and treat it as a compiler error if you break them.
+ *
+ * @param {!Object} me Should always be "this".
+ * @param {*=} opt_methodName The method name if calling a super method.
+ * @param {...*} var_args The rest of the arguments.
+ * @return {*} The return value of the superclass method.
+ * @suppress {es5Strict} This method can not be used in strict mode, but
+ *     all Closure Library consumers must depend on this file.
+ */
+goog.base = function(me, opt_methodName, var_args) {
+  var caller = arguments.callee.caller;
+
+  if (goog.STRICT_MODE_COMPATIBLE || (goog.DEBUG && !caller)) {
+    throw Error('arguments.caller not defined.  goog.base() cannot be used ' +
+                'with strict mode code. See ' +
+                'http://www.ecma-international.org/ecma-262/5.1/#sec-C');
+  }
+
+  if (caller.superClass_) {
+    // Copying using loop to avoid deop due to passing arguments object to
+    // function. This is faster in many JS engines as of late 2014.
+    var ctorArgs = new Array(arguments.length - 1);
+    for (var i = 1; i < arguments.length; i++) {
+      ctorArgs[i - 1] = arguments[i];
+    }
+    // This is a constructor. Call the superclass constructor.
+    return caller.superClass_.constructor.apply(me, ctorArgs);
+  }
+
+  // Copying using loop to avoid deop due to passing arguments object to
+  // function. This is faster in many JS engines as of late 2014.
+  var args = new Array(arguments.length - 2);
+  for (var i = 2; i < arguments.length; i++) {
+    args[i - 2] = arguments[i];
+  }
+  var foundCaller = false;
+  for (var ctor = me.constructor;
+       ctor; ctor = ctor.superClass_ && ctor.superClass_.constructor) {
+    if (ctor.prototype[opt_methodName] === caller) {
+      foundCaller = true;
+    } else if (foundCaller) {
+      return ctor.prototype[opt_methodName].apply(me, args);
+    }
+  }
+
+  // If we did not find the caller in the prototype chain, then one of two
+  // things happened:
+  // 1) The caller is an instance method.
+  // 2) This method was not called by the right caller.
+  if (me[opt_methodName] === caller) {
+    return me.constructor.prototype[opt_methodName].apply(me, args);
+  } else {
+    throw Error(
+        'goog.base called from a method of one name ' +
+        'to a method of a different name');
+  }
+};
+
+
+/**
+ * Allow for aliasing within scope functions.  This function exists for
+ * uncompiled code - in compiled code the calls will be inlined and the aliases
+ * applied.  In uncompiled code the function is simply run since the aliases as
+ * written are valid JavaScript.
+ *
+ *
+ * @param {function()} fn Function to call.  This function can contain aliases
+ *     to namespaces (e.g. "var dom = goog.dom") or classes
+ *     (e.g. "var Timer = goog.Timer").
+ */
+goog.scope = function(fn) {
+  fn.call(goog.global);
+};
+
+
+/*
+ * To support uncompiled, strict mode bundles that use eval to divide source
+ * like so:
+ *    eval('someSource;//# sourceUrl sourcefile.js');
+ * We need to export the globally defined symbols "goog" and "COMPILED".
+ * Exporting "goog" breaks the compiler optimizations, so we required that
+ * be defined externally.
+ * NOTE: We don't use goog.exportSymbol here because we don't want to trigger
+ * extern generation when that compiler option is enabled.
+ */
+if (!COMPILED) {
+  goog.global['COMPILED'] = COMPILED;
+}
+
+
+
+//==============================================================================
+// goog.defineClass implementation
+//==============================================================================
+
+
+/**
+ * Creates a restricted form of a Closure "class":
+ *   - from the compiler's perspective, the instance returned from the
+ *     constructor is sealed (no new properties may be added).  This enables
+ *     better checks.
+ *   - the compiler will rewrite this definition to a form that is optimal
+ *     for type checking and optimization (initially this will be a more
+ *     traditional form).
+ *
+ * @param {Function} superClass The superclass, Object or null.
+ * @param {goog.defineClass.ClassDescriptor} def
+ *     An object literal describing
+ *     the class.  It may have the following properties:
+ *     "constructor": the constructor function
+ *     "statics": an object literal containing methods to add to the constructor
+ *        as "static" methods or a function that will receive the constructor
+ *        function as its only parameter to which static properties can
+ *        be added.
+ *     all other properties are added to the prototype.
+ * @return {!Function} The class constructor.
+ */
+goog.defineClass = function(superClass, def) {
+  // TODO(johnlenz): consider making the superClass an optional parameter.
+  var constructor = def.constructor;
+  var statics = def.statics;
+  // Wrap the constructor prior to setting up the prototype and static methods.
+  if (!constructor || constructor == Object.prototype.constructor) {
+    constructor = function() {
+      throw Error('cannot instantiate an interface (no constructor defined).');
+    };
+  }
+
+  var cls = goog.defineClass.createSealingConstructor_(constructor, superClass);
+  if (superClass) {
+    goog.inherits(cls, superClass);
+  }
+
+  // Remove all the properties that should not be copied to the prototype.
+  delete def.constructor;
+  delete def.statics;
+
+  goog.defineClass.applyProperties_(cls.prototype, def);
+  if (statics != null) {
+    if (statics instanceof Function) {
+      statics(cls);
+    } else {
+      goog.defineClass.applyProperties_(cls, statics);
+    }
+  }
+
+  return cls;
+};
+
+
+/**
+ * @typedef {
+ *     !Object|
+ *     {constructor:!Function}|
+ *     {constructor:!Function, statics:(Object|function(Function):void)}}
+ * @suppress {missingProvide}
+ */
+goog.defineClass.ClassDescriptor;
+
+
+/**
+ * @define {boolean} Whether the instances returned by
+ * goog.defineClass should be sealed when possible.
+ */
+goog.define('goog.defineClass.SEAL_CLASS_INSTANCES', goog.DEBUG);
+
+
+/**
+ * If goog.defineClass.SEAL_CLASS_INSTANCES is enabled and Object.seal is
+ * defined, this function will wrap the constructor in a function that seals the
+ * results of the provided constructor function.
+ *
+ * @param {!Function} ctr The constructor whose results maybe be sealed.
+ * @param {Function} superClass The superclass constructor.
+ * @return {!Function} The replacement constructor.
+ * @private
+ */
+goog.defineClass.createSealingConstructor_ = function(ctr, superClass) {
+  if (goog.defineClass.SEAL_CLASS_INSTANCES &&
+      Object.seal instanceof Function) {
+    // Don't seal subclasses of unsealable-tagged legacy classes.
+    if (superClass && superClass.prototype &&
+        superClass.prototype[goog.UNSEALABLE_CONSTRUCTOR_PROPERTY_]) {
+      return ctr;
+    }
+    /**
+     * @this {Object}
+     * @return {?}
+     */
+    var wrappedCtr = function() {
+      // Don't seal an instance of a subclass when it calls the constructor of
+      // its super class as there is most likely still setup to do.
+      var instance = ctr.apply(this, arguments) || this;
+      instance[goog.UID_PROPERTY_] = instance[goog.UID_PROPERTY_];
+      if (this.constructor === wrappedCtr) {
+        Object.seal(instance);
+      }
+      return instance;
+    };
+    return wrappedCtr;
+  }
+  return ctr;
+};
+
+
+// TODO(johnlenz): share these values with the goog.object
+/**
+ * The names of the fields that are defined on Object.prototype.
+ * @type {!Array<string>}
+ * @private
+ * @const
+ */
+goog.defineClass.OBJECT_PROTOTYPE_FIELDS_ = [
+  'constructor',
+  'hasOwnProperty',
+  'isPrototypeOf',
+  'propertyIsEnumerable',
+  'toLocaleString',
+  'toString',
+  'valueOf'
+];
+
+
+// TODO(johnlenz): share this function with the goog.object
+/**
+ * @param {!Object} target The object to add properties to.
+ * @param {!Object} source The object to copy properties from.
+ * @private
+ */
+goog.defineClass.applyProperties_ = function(target, source) {
+  // TODO(johnlenz): update this to support ES5 getters/setters
+
+  var key;
+  for (key in source) {
+    if (Object.prototype.hasOwnProperty.call(source, key)) {
+      target[key] = source[key];
+    }
+  }
+
+  // For IE the for-in-loop does not contain any properties that are not
+  // enumerable on the prototype object (for example isPrototypeOf from
+  // Object.prototype) and it will also not include 'replace' on objects that
+  // extend String and change 'replace' (not that it is common for anyone to
+  // extend anything except Object).
+  for (var i = 0; i < goog.defineClass.OBJECT_PROTOTYPE_FIELDS_.length; i++) {
+    key = goog.defineClass.OBJECT_PROTOTYPE_FIELDS_[i];
+    if (Object.prototype.hasOwnProperty.call(source, key)) {
+      target[key] = source[key];
+    }
+  }
+};
+
+
+/**
+ * Sealing classes breaks the older idiom of assigning properties on the
+ * prototype rather than in the constructor.  As such, goog.defineClass
+ * must not seal subclasses of these old-style classes until they are fixed.
+ * Until then, this marks a class as "broken", instructing defineClass
+ * not to seal subclasses.
+ * @param {!Function} ctr The legacy constructor to tag as unsealable.
+ */
+goog.tagUnsealableClass = function(ctr) {
+  if (!COMPILED && goog.defineClass.SEAL_CLASS_INSTANCES) {
+    ctr.prototype[goog.UNSEALABLE_CONSTRUCTOR_PROPERTY_] = true;
+  }
+};
+
+
+/**
+ * Name for unsealable tag property.
+ * @const @private {string}
+ */
+goog.UNSEALABLE_CONSTRUCTOR_PROPERTY_ = 'goog_defineClass_legacy_unsealable';