Fix initial prototype of WeakMap function.

src/bootstrapper.cc

 // 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 1142 matching lines @@
                              code,
                              true);
 
     Handle<String> name = factory->LookupAsciiSymbol("context_extension");
     context_extension_fun->shared()->set_instance_class_name(*name);
     global_context()->set_context_extension_function(*context_extension_fun);
   }
 
 
   {
-    // Setup the call-as-function delegate.
+    // Set up the call-as-function delegate.
     Handle<Code> code =
         Handle<Code>(isolate->builtins()->builtin(
             Builtins::kHandleApiCallAsFunction));
     Handle<JSFunction> delegate =
         factory->NewFunction(factory->empty_symbol(), JS_OBJECT_TYPE,
                              JSObject::kHeaderSize, code, true);
     global_context()->set_call_as_function_delegate(*delegate);
     delegate->shared()->DontAdaptArguments();
   }
 
   {
-    // Setup the call-as-constructor delegate.
+    // Set up the call-as-constructor delegate.
     Handle<Code> code =
         Handle<Code>(isolate->builtins()->builtin(
             Builtins::kHandleApiCallAsConstructor));
     Handle<JSFunction> delegate =
         factory->NewFunction(factory->empty_symbol(), JS_OBJECT_TYPE,
                              JSObject::kHeaderSize, code, true);
     global_context()->set_call_as_constructor_delegate(*delegate);
     delegate->shared()->DontAdaptArguments();
   }
 
   // Initialize the out of memory slot.
   global_context()->set_out_of_memory(heap->false_value());
 
   // Initialize the data slot.
   global_context()->set_data(heap->undefined_value());
 }
 
 
 void Genesis::InitializeExperimentalGlobal() {
-  Isolate* isolate = this->isolate();
   Handle<JSObject> global = Handle<JSObject>(global_context()->global());
 
   // TODO(mstarzinger): Move this into Genesis::InitializeGlobal once we no
   // longer need to live behind a flag, so WeakMap gets added to the snapshot.
   if (FLAG_harmony_weakmaps) {  // -- W e a k M a p
+    Handle<JSObject> prototype =
+        factory()->NewJSObject(isolate()->object_function(), TENURED);
     InstallFunction(global, "WeakMap", JS_WEAK_MAP_TYPE, JSWeakMap::kSize,
-                    isolate->initial_object_prototype(),
-                    Builtins::kIllegal, true);
+                    prototype, Builtins::kIllegal, true);
   }
 }
 
 
 bool Genesis::CompileBuiltin(Isolate* isolate, int index) {
   Vector<const char> name = Natives::GetScriptName(index);
   Handle<String> source_code =
       isolate->bootstrapper()->NativesSourceLookup(index);
   return CompileNative(name, source_code);
 }
@@ skipping 1005 matching lines @@
   return from + sizeof(NestingCounterType);
 }
 
 
 // Called when the top-level V8 mutex is destroyed.
 void Bootstrapper::FreeThreadResources() {
   ASSERT(!IsActive());
 }
 
 } }  // namespace v8::internal