Introduce kGCCallbackForced flag.

src/extensions/gc-extension.cc

 // Copyright 2010 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 24 matching lines @@
 v8::Handle<v8::FunctionTemplate> GCExtension::GetNativeFunctionTemplate(
     v8::Isolate* isolate,
     v8::Handle<v8::String> str) {
   return v8::FunctionTemplate::New(GCExtension::GC);
 }
 
 
 void GCExtension::GC(const v8::FunctionCallbackInfo<v8::Value>& args) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(args.GetIsolate());
   if (args[0]->BooleanValue()) {
-    isolate->heap()->CollectGarbage(NEW_SPACE, "gc extension");
+    isolate->heap()->CollectGarbage(
+        NEW_SPACE, "gc extension", v8::kGCCallbackForced);
   } else {
-    isolate->heap()->CollectAllGarbage(Heap::kNoGCFlags, "gc extension");
+    isolate->heap()->CollectAllGarbage(
+        Heap::kNoGCFlags, "gc extension", v8::kGCCallbackForced);
   }
 }
 
 
 void GCExtension::Register() {
   static char buffer[50];
   Vector<char> temp_vector(buffer, sizeof(buffer));
   if (FLAG_expose_gc_as != NULL && strlen(FLAG_expose_gc_as) != 0) {
     OS::SNPrintF(temp_vector, "native function %s();", FLAG_expose_gc_as);
   } else {
     OS::SNPrintF(temp_vector, "native function gc();");
   }
 
   static GCExtension gc_extension(buffer);
   static v8::DeclareExtension declaration(&gc_extension);
 }
 
 } }  // namespace v8::internal