Implement handlified String::Equals and Name::Equals.

src/heap.h

 // Copyright 2012 the V8 project authors. 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
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1171 matching lines @@
   MUST_USE_RESULT MaybeObject* InternalizeString(String* str);
   MUST_USE_RESULT MaybeObject* InternalizeStringWithKey(HashTableKey* key);
 
   bool InternalizeStringIfExists(String* str, String** result);
   bool InternalizeTwoCharsStringIfExists(String* str, String** result);
 
   // Compute the matching internalized string map for a string if possible.
   // NULL is returned if string is in new space or not flattened.
   Map* InternalizedStringMapForString(String* str);
 
-  // Tries to flatten a string before compare operation.
-  //
-  // Returns a failure in case it was decided that flattening was
-  // necessary and failed.  Note, if flattening is not necessary the
-  // string might stay non-flat even when not a failure is returned.
-  //
-  // Please note this function does not perform a garbage collection.
-  MUST_USE_RESULT inline MaybeObject* PrepareForCompare(String* str);
-
   // Converts the given boolean condition to JavaScript boolean value.
   inline Object* ToBoolean(bool condition);
 
   // Performs garbage collection operation.
   // Returns whether there is a chance that another major GC could
   // collect more garbage.
   inline bool CollectGarbage(
       AllocationSpace space,
       const char* gc_reason = NULL,
       const GCCallbackFlags gc_callback_flags = kNoGCCallbackFlags);
@@ skipping 1873 matching lines @@
   DisallowHeapAllocation no_allocation;  // i.e. no gc allowed.
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
 };
 #endif  // DEBUG
 
 } }  // namespace v8::internal
 
 #endif  // V8_HEAP_H_