Make assertion scopes thread safe.

include/v8.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 4140 matching lines @@
 };
 
 
 /**
  * Asserts that no action is performed that could cause a handle's value
  * to be modified. Useful when otherwise unsafe handle operations need to
  * be performed.
  */
 class V8EXPORT AssertNoGCScope {
 #ifndef DEBUG
-  V8_INLINE(AssertNoGCScope(Isolate* isolate)) {}
+  // TODO(yangguo): remove isolate argument.
+  V8_INLINE(AssertNoGCScope(Isolate* isolate)) { }
 #else
   AssertNoGCScope(Isolate* isolate);
   ~AssertNoGCScope();
  private:
-  Isolate* isolate_;
-  bool last_state_;
+  void* disallow_heap_allocation_;
 #endif
 };
 
 
 /**
  * Container class for static utility functions.
  */
 class V8EXPORT V8 {
  public:
   /** Set the callback to invoke in case of fatal errors. */
@@ skipping 2125 matching lines @@
 
 
 }  // namespace v8
 
 
 #undef V8EXPORT
 #undef TYPE_CHECK
 
 
 #endif  // V8_H_