Fix top renderer crash. Extension can go away before Context. Duh.

chrome/renderer/extensions/chrome_v8_context.h

 // Copyright (c) 2012 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 CHROME_RENDERER_EXTENSIONS_CHROME_V8_CONTEXT_H_
 #define CHROME_RENDERER_EXTENSIONS_CHROME_V8_CONTEXT_H_
 #pragma once
 
 #include <string>
 
@@ skipping 21 matching lines @@
                   WebKit::WebFrame* frame,
                   const Extension* extension,
                   extensions::Feature::Context context_type);
   ~ChromeV8Context();
 
   v8::Handle<v8::Context> v8_context() const {
     return v8_context_;
   }
 
   const Extension* extension() const {
-    return extension_;
+    return extension_.get();
   }
 
   WebKit::WebFrame* web_frame() const {
     return web_frame_;
   }
   void clear_web_frame() {
     web_frame_ = NULL;
   }
 
   extensions::Feature::Context context_type() const {
@@ skipping 54 matching lines @@
   // since the DOM keeps the context alive, but it makes things simpler to not
   // distinguish the two cases.
   v8::Persistent<v8::Context> v8_context_;
 
   // The WebFrame associated with this context. This can be NULL because this
   // object can outlive is destroyed asynchronously.
   WebKit::WebFrame* web_frame_;
 
   // The extension associated with this context, or NULL if there is none. This
   // might be a hosted app in the case that this context is hosting a web URL.
-  const Extension* extension_;
+  scoped_refptr<const Extension> extension_;
 
   // The type of context.
   extensions::Feature::Context context_type_;
 
   // Owns and structures the JS that is injected to set up extension bindings.
   scoped_ptr<ModuleSystem> module_system_;
 
   // The extension APIs available to this context.
   scoped_ptr<std::set<std::string> > available_extension_apis_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeV8Context);
 };
 
 #endif  // CHROME_RENDERER_EXTENSIONS_CHROME_V8_CONTEXT_H_