Add build manifest and PolymerLoader

- Depends on WeakMap

build.json

@@ -0,0 +1,4 @@
+[
+  "../WeakMap/weakmap.js",
+  "MutationObserver.js"
+]

mutation-observers.js

@@ -0,0 +1,35 @@
+/*
+ * Copyright 2013 The Polymer Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style
+ * license that can be found in the LICENSE file.
+ */
+
+(function() {
+
+var thisFile = 'mutation-observers.js';
+var scopeName = 'MutationObservers';
+var modules = [
+  '../WeakMap/weakmap.js',
+  'MutationObserver.js',
+];
+
+// export
+
+window[scopeName] = {
+  entryPointName: thisFile,
+  modules: modules
+};
+
+// bootstrap
+
+var script = document.querySelector('script[src*="' + thisFile + '"]');
+var src = script.attributes.src.value;
+var basePath = src.slice(0, src.indexOf(thisFile));
+
+if (!window.PolymerLoader) {
+  var path = basePath + '../tools/loader/loader.js';
+  document.write('<script src="' + path + '"></script>');
+}
+document.write('<script>PolymerLoader.load("' + scopeName + '")</script>');
+
+})();