Refactor rhino code to work around internal Google

limitation on Java 8 use.
After this change Java 8 can be used anywhere except in
TokenStream and JSIdentifier.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=188559755

src/com/google/javascript/jscomp/gwt/super/com/google/javascript/rhino/JSIdentifier.java

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2018 The Closure Compiler Authors.
+ *
+ * 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.
+ */
+
+package com.google.javascript.rhino;
+
+import jsinterop.annotations.JsPackage;
+import jsinterop.annotations.JsType;
+
+/** Determines whether a string is a valid JS identifier. */
+public class JSIdentifier {
+  @JsType(isNative = true, namespace = JsPackage.GLOBAL, name = "RegExp")
+  private static class RegExp {
+    RegExp(String string) {}
+    native boolean test(String string);
+    native boolean test(int charcode);
+  }
+
+  // TODO(moz): Support full range of valid characters.
+  private static final RegExp JS_IDENTIFIER_REGEX = new RegExp("^[a-zA-Z_$][\\w$]*$");
+
+  /** Determines whether a string is a valid JS identifier. */
+  public static boolean isJSIdentifier(String s) {
+    return JS_IDENTIFIER_REGEX.test(s);
+  }
+}

src/com/google/javascript/jscomp/gwt/super/com/google/javascript/rhino/TokenUtil.java

@@ -33,14 +33,8 @@ private static class RegExp {
     native boolean test(int charcode);
   }
 
-  // TODO(moz): Support full range of valid characters.
-  private static final RegExp JS_IDENTIFIER_REGEX = new RegExp("^[a-zA-Z_$][\\w$]*$");
   private static final RegExp WHITE_SPACE_REGEX = new RegExp("\\s");
 
-  static boolean isJSIdentifier(String s) {
-    return JS_IDENTIFIER_REGEX.test(s);
-  }
-
   public static boolean isJSSpace(int c) {
     if (c <= 127) {
       return c == 0x20 || c == 0x9 || c == 0xC || c == 0xB;

src/com/google/javascript/rhino/JSIdentifier.java

@@ -0,0 +1,77 @@
+/*
+ *
+ * ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (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.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is Rhino code, released
+ * May 6, 1999.
+ *
+ * The Initial Developer of the Original Code is
+ * Netscape Communications Corporation.
+ * Portions created by the Initial Developer are Copyright (C) 1997-1999
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *   Roger Lawrence
+ *   Mike McCabe
+ *   Igor Bukanov
+ *   Ethan Hugg
+ *   Bob Jervis
+ *   Terry Lucas
+ *   Milen Nankov
+ *   Pascal-Louis Perez
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * the GNU General Public License Version 2 or later (the "GPL"), in which
+ * case the provisions of the GPL are applicable instead of those above. If
+ * you wish to allow use of your version of this file only under the terms of
+ * the GPL and not to allow others to use your version of this file under the
+ * MPL, indicate your decision by deleting the provisions above and replacing
+ * them with the notice and other provisions required by the GPL. If you do
+ * not delete the provisions above, a recipient may use your version of this
+ * file under either the MPL or the GPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+package com.google.javascript.rhino;
+
+import com.google.common.annotations.GwtIncompatible;
+
+/**
+ * Utility class to hold isJSIdentifier.
+ *
+ * <p>Separated into its own class because it is not GWT compatible.
+ *
+ * IMPORTANT: As of 2018-03-09 it is still not possible to use Java 8 features in this file
+ * due to limitations on some internal Google projects that depend on it.
+ */
+@GwtIncompatible
+public class JSIdentifier {
+  static boolean isJSIdentifier(String s) {
+    int length = s.length();
+
+    if (length == 0
+        || Character.isIdentifierIgnorable(s.charAt(0))
+        || !Character.isJavaIdentifierStart(s.charAt(0))) {
+      return false;
+    }
+
+    for (int i = 1; i < length; i++) {
+      if (Character.isIdentifierIgnorable(s.charAt(i))
+          || !Character.isJavaIdentifierPart(s.charAt(i))) {
+        return false;
+      }
+    }
+    return true;
+  }
+}

src/com/google/javascript/rhino/TokenStream.java

@@ -51,8 +51,10 @@
  * It is based on the C source files jsscan.c and jsscan.h
  * in the jsref package.
  *
+ *
+ * IMPORTANT: As of 2018-03-09 it is still not possible to use Java 8 features in this file
+ * due to limitations on some internal Google projects that depend on it.
  */
-
 public class TokenStream {
    public static boolean isKeyword(String name) {
         boolean id = false;
@@ -187,7 +189,7 @@ else if (c=='s') {
         return id;
     }
 
-    public static boolean isJSIdentifier(String s) {
-      return TokenUtil.isJSIdentifier(s);
-    }
+  public static boolean isJSIdentifier(String s) {
+    return JSIdentifier.isJSIdentifier(s);
+  }
 }

src/com/google/javascript/rhino/TokenUtil.java

@@ -56,24 +56,6 @@
  */
 @GwtIncompatible("Unsupported java.lang.Character fields")
 public class TokenUtil {
-  static boolean isJSIdentifier(String s) {
-    int length = s.length();
-
-    if (length == 0
-        || Character.isIdentifierIgnorable(s.charAt(0))
-        || !Character.isJavaIdentifierStart(s.charAt(0))) {
-      return false;
-    }
-
-    for (int i = 1; i < length; i++) {
-      if (Character.isIdentifierIgnorable(s.charAt(i))
-          || !Character.isJavaIdentifierPart(s.charAt(i))) {
-        return false;
-      }
-    }
-    return true;
-  }
-
   /* As defined in ECMA.  jsscan.c uses C isspace() (which allows
    * \v, I think.)  note that code in getChar() implicitly accepts
    * '\r' == \u000D as well.