[bindings] Bindings should only support the prescribed types for constants.

Source/bindings/tests/idls/core/TestObject.idl

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 24 matching lines @@
 
 // No extended attributes on the interface; those go in TestInterface.idl
 interface TestObject {
     // Constants
     const unsigned short CONST_VALUE_0 = 0;
     const unsigned short CONST_VALUE_1 = 1;
     const unsigned short CONST_VALUE_2 = 2;
     const unsigned short CONST_VALUE_4 = 4;
     const unsigned short CONST_VALUE_8 = 8;
     const short CONST_VALUE_9 = -1;
-    const DOMString CONST_VALUE_10 = "my constant string";
     const unsigned short CONST_VALUE_11 = 0xffffffff;
     const unsigned short CONST_VALUE_12 = 0x01;
     const unsigned short CONST_VALUE_13 = 0X20;
     const unsigned short CONST_VALUE_14 = 0x1abc;
     const unsigned short CONST_VALUE_15 = 010;
     const unsigned short CONST_VALUE_16 = -010;
     const unsigned short CONST_VALUE_16 = -0x1A;
     const unsigned short CONST_VALUE_17 = -0X1a;
     const double CONST_VALUE_18 = 0.123;
     const double CONST_VALUE_19 = 4e9;
@@ skipping 552 matching lines @@
     [ImplementedInPrivateScript] attribute DOMString stringAttribute;
     [ImplementedInPrivateScript] attribute Node nodeAttribute;
     [OnlyExposedToPrivateScript] short methodImplementedInCPPForPrivateScriptOnly(short value1, short value2);
     [OnlyExposedToPrivateScript] attribute DOMString attributeImplementedInCPPForPrivateScriptOnly;
     [ImplementedInPrivateScript, OnlyExposedToPrivateScript] short methodForPrivateScriptOnly(short value1, short value2);
     [ImplementedInPrivateScript, OnlyExposedToPrivateScript] attribute DOMString attributeForPrivateScriptOnly;
     [ImplementedInPrivateScript] attribute TestEnum enumForPrivateScript;
 
     maplike<long, DOMStringOrDouble>;
 };