Make sure we register extensions only once. Removed unused member variable.

src/bootstrapper.cc

 // 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 77 matching lines @@
     heap->natives_source_cache()->set(index, *source_code);
   }
   Handle<Object> cached_source(heap->natives_source_cache()->get(index),
                                isolate_);
   return Handle<String>::cast(cached_source);
 }
 
 
 void Bootstrapper::Initialize(bool create_heap_objects) {
   extensions_cache_.Initialize(create_heap_objects);
+}
+
+
+void Bootstrapper::InitializeOncePerProcess() {
   GCExtension::Register();
   ExternalizeStringExtension::Register();
   StatisticsExtension::Register();
 }
 
 
 char* Bootstrapper::AllocateAutoDeletedArray(int bytes) {
   char* memory = new char[bytes];
   if (memory != NULL) {
     if (delete_these_arrays_on_tear_down_ == NULL) {
@@ skipping 2518 matching lines @@
   return from + sizeof(NestingCounterType);
 }
 
 
 // Called when the top-level V8 mutex is destroyed.
 void Bootstrapper::FreeThreadResources() {
   ASSERT(!IsActive());
 }
 
 } }  // namespace v8::internal