Removed a bunch of GetExistingThreadLocal calls by threading the Isolate.

src/handles.h

 // Copyright 2011 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 79 matching lines @@
   // implementation in api.h.
   inline Handle<T> EscapeFrom(v8::HandleScope* scope);
 
  private:
   T** location_;
 };
 
 
 // Convenience wrapper.
 template<class T>
-inline Handle<T> handle(T* t) {
-  return Handle<T>(t);
+inline Handle<T> handle(T* t, Isolate* isolate) {
+  return Handle<T>(t, isolate);
 }
 
 
 class DeferredHandles;
 class HandleScopeImplementer;
 
 
 // A stack-allocated class that governs a number of local handles.
 // After a handle scope has been created, all local handles will be
 // allocated within that handle scope until either the handle scope is
@@ skipping 224 matching lines @@
   inline ~NoHandleAllocation();
  private:
   int level_;
   bool active_;
 #endif
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_HANDLES_H_