Make LoadMonitoringExtensionHostQueue remove itself as an ExtensionHost observer at the correct tim…

extensions/browser/extension_host.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_BROWSER_EXTENSION_HOST_H_
 #define EXTENSIONS_BROWSER_EXTENSION_HOST_H_
 
 #include <set>
 #include <string>
 
@@ skipping 41 matching lines @@
   ExtensionHost(const Extension* extension,
                 content::SiteInstance* site_instance,
                 const GURL& url, ViewType host_type);
   ~ExtensionHost() override;
 
   const Extension* extension() const { return extension_; }
   const std::string& extension_id() const { return extension_id_; }
   content::WebContents* host_contents() const { return host_contents_.get(); }
   content::RenderViewHost* render_view_host() const;
   content::RenderProcessHost* render_process_host() const;
-  bool did_stop_loading() const { return did_stop_loading_; }
+  bool has_loaded_once() const { return has_loaded_once_; }
   bool document_element_available() const {
     return document_element_available_;
   }
 
   content::BrowserContext* browser_context() { return browser_context_; }
 
   ViewType extension_host_type() const { return extension_host_type_; }
   const GURL& GetURL() const;
 
   // Returns true if the render view is initialized and didn't crash.
@@ skipping 51 matching lines @@
                                   const GURL& security_origin,
                                   content::MediaStreamType type) override;
   bool IsNeverVisible(content::WebContents* web_contents) override;
 
   // ExtensionRegistryObserver:
   void OnExtensionUnloaded(content::BrowserContext* browser_context,
                            const Extension* extension,
                            UnloadedExtensionInfo::Reason reason) override;
 
  protected:
-  // Called after the extension page finishes loading but before the
-  // EXTENSION_HOST_DID_STOP_LOADING notification is sent.
+  // Called each time this ExtensionHost completes a load finishes loading,
+  // before any stop-loading notifications or observer methods are called.
   virtual void OnDidStopLoading();
 
   // Navigates to the initial page.
   virtual void LoadInitialURL();
 
   // Returns true if we're hosting a background page.
   virtual bool IsBackgroundPage() const;
 
  private:
   // DeferredStartRenderHost:
   void CreateRenderViewNow() override;
   void AddDeferredStartRenderHostObserver(
       DeferredStartRenderHostObserver* observer) override;
   void RemoveDeferredStartRenderHostObserver(
       DeferredStartRenderHostObserver* observer) override;
 
   // Message handlers.
   void OnRequest(const ExtensionHostMsg_Request_Params& params);
   void OnEventAck(int event_id);
   void OnIncrementLazyKeepaliveCount();
   void OnDecrementLazyKeepaliveCount();
 
+  // Records UMA for load events. Called both from DidStopLoading and from the
+  // destructor.
+  void RecordStopLoadingUMA();
+
   // Delegate for functionality that cannot exist in the extensions module.
   scoped_ptr<ExtensionHostDelegate> delegate_;
 
   // The extension that we're hosting in this view.
   const Extension* extension_;
 
   // Id of extension that we're hosting in this view.
   const std::string extension_id_;
 
   // The browser context that this host is tied to.
   content::BrowserContext* browser_context_;
 
   // The host for our HTML content.
   scoped_ptr<content::WebContents> host_contents_;
 
   // A weak pointer to the current or pending RenderViewHost. We don't access
   // this through the host_contents because we want to deal with the pending
   // host, so we can send messages to it before it finishes loading.
   content::RenderViewHost* render_view_host_;
 
-  // Whether the RenderWidget has reported that it has stopped loading.
-  bool did_stop_loading_;
+  // Whether the ExtensionHost is currently in the process of loading, i.e. if
+  // the DidStartLoading event has fired but the DidStopLoading event hasn't.
+  bool is_loading_;
+
+  // Whether the ExtensionHost has finished loading some content at least once.
+  // There may be subsequent loads - such as reloads and navigations - and this
+  // will not affect its value (it will remain true).
+  bool has_loaded_once_;
 
   // True if the main frame has finished parsing.
   bool document_element_available_;
 
   // The original URL of the page being hosted.
   GURL initial_url_;
 
   // Messages sent out to the renderer that have not been acknowledged yet.
   std::set<int> unacked_messages_;
 
   ExtensionFunctionDispatcher extension_function_dispatcher_;
 
   // The type of view being hosted.
   ViewType extension_host_type_;
 
   // Measures how long since the initial URL started loading.
   scoped_ptr<base::ElapsedTimer> load_start_;
 
   ObserverList<ExtensionHostObserver> observer_list_;
   ObserverList<DeferredStartRenderHostObserver>
       deferred_start_render_host_observer_list_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionHost);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_EXTENSION_HOST_H_