Add fallback mechanism to release Extension ports if the JS context has been destroyed.

extensions/renderer/script_context.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef EXTENSIONS_RENDERER_SCRIPT_CONTEXT_H_
 #define EXTENSIONS_RENDERER_SCRIPT_CONTEXT_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 90 matching lines @@
   content::RenderView* GetRenderView() const;
 
   // Returns the RenderFrame associated with this context. Can return NULL if
   // the context is in the process of being destroyed.
   content::RenderFrame* GetRenderFrame() const;
 
   // Runs |function| with appropriate scopes. Doesn't catch exceptions, callers
   // must do that if they want.
   //
   // USE THIS METHOD RATHER THAN v8::Function::Call WHEREVER POSSIBLE.
-  v8::Local<v8::Value> CallFunction(v8::Local<v8::Function> function,
+  v8::Local<v8::Value> CallFunction(const v8::Local<v8::Function>& function,
                                     int argc,
                                     v8::Local<v8::Value> argv[]) const;
+  v8::Local<v8::Value> CallFunction(
+      const v8::Local<v8::Function>& function) const;
 
   void DispatchEvent(const char* event_name, v8::Local<v8::Array> args) const;
 
   // Fires the onunload event on the unload_event module.
   void DispatchOnUnloadEvent();
 
   // Returns the availability of the API |api_name|.
   Feature::Availability GetAvailability(const std::string& api_name);
 
   // Returns a string description of the type of context this is.
@@ skipping 100 matching lines @@
   GURL url_;
 
   scoped_ptr<Runner> runner_;
 
   DISALLOW_COPY_AND_ASSIGN(ScriptContext);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_RENDERER_SCRIPT_CONTEXT_H_