[ABANDONED] Call Microtask::performCheckpoint for each worker task.

Source/bindings/v8/V8PerIsolateData.h

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 75 matching lines @@
     GCEventData* gcEventData() { return m_gcEventData.get(); }
     V8HiddenValue* hiddenValue() { return m_hiddenValue.get(); }
 
     v8::Handle<v8::FunctionTemplate> domTemplate(void* domTemplateKey, v8::FunctionCallback = 0, v8::Handle<v8::Value> data = v8::Handle<v8::Value>(), v8::Handle<v8::Signature> = v8::Handle<v8::Signature>(), int length = 0);
     v8::Handle<v8::FunctionTemplate> existingDOMTemplate(void* domTemplateKey);
     void setDOMTemplate(void* domTemplateKey, v8::Handle<v8::FunctionTemplate>);
 
     bool hasInstance(const WrapperTypeInfo*, v8::Handle<v8::Value>);
     v8::Handle<v8::Object> findInstanceInPrototypeChain(const WrapperTypeInfo*, v8::Handle<v8::Value>);
 
+    // This method may return an empty handle when the script execution
+    // is terminated.
     v8::Local<v8::Context> ensureDomInJSContext();
 
     const char* previousSamplingState() const { return m_previousSamplingState; }
     void setPreviousSamplingState(const char* name) { m_previousSamplingState = name; }
 
 private:
     explicit V8PerIsolateData(v8::Isolate*);
     ~V8PerIsolateData();
 
     typedef HashMap<const void*, v8::Eternal<v8::FunctionTemplate> > DOMTemplateMap;
@@ skipping 21 matching lines @@
 #ifndef NDEBUG
     int m_internalScriptRecursionLevel;
 #endif
     OwnPtr<GCEventData> m_gcEventData;
     bool m_performingMicrotaskCheckpoint;
 };
 
 } // namespace WebCore
 
 #endif // V8PerIsolateData_h