Removing unnecessary creation of RenderViewHostDestructionObserver for all WebContents

extensions/browser/process_manager.h

 // Copyright 2013 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_BROWSER_PROCESS_MANAGER_H_
 #define EXTENSIONS_BROWSER_PROCESS_MANAGER_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 172 matching lines @@
   // These are called when the extension transitions between idle and active.
   // They control the process of closing the background page when idle.
   void OnLazyBackgroundPageIdle(const std::string& extension_id,
                                 int sequence_id);
   void OnLazyBackgroundPageActive(const std::string& extension_id);
   void CloseLazyBackgroundPageNow(const std::string& extension_id,
                                   int sequence_id);
 
   // Potentially registers a RenderViewHost, if it is associated with an
   // extension. Does nothing if this is not an extension renderer.
-  void RegisterRenderViewHost(content::RenderViewHost* render_view_host);
+  // Returns true, if render_view_host was registered (it is associated
+  // with an extension).
+  bool RegisterRenderViewHost(content::RenderViewHost* render_view_host);
 
   // Unregister RenderViewHosts and clear background page data for an extension
   // which has been unloaded.
   void UnregisterExtension(const std::string& extension_id);
 
   // Clears background page data for this extension.
   void ClearBackgroundPageData(const std::string& extension_id);
 
   // Returns true if loading background pages should be deferred.
   bool DeferLoadingBackgroundHosts() const;
@@ skipping 24 matching lines @@
   ImpulseCallbackForTesting keepalive_impulse_decrement_callback_for_testing_;
 
   base::WeakPtrFactory<ProcessManager> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ProcessManager);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_PROCESS_MANAGER_H_