Modify the RenderThread to track the number of widgets...

chrome/renderer/render_thread.h

 // Copyright (c) 2009 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_RENDER_THREAD_H_
 #define CHROME_RENDERER_RENDER_THREAD_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 31 matching lines @@
 
   virtual bool Send(IPC::Message* msg) = 0;
 
   // Called to add or remove a listener for a particular message routing ID.
   // These methods normally get delegated to a MessageRouter.
   virtual void AddRoute(int32 routing_id, IPC::Channel::Listener* listener) = 0;
   virtual void RemoveRoute(int32 routing_id) = 0;
 
   virtual void AddFilter(IPC::ChannelProxy::MessageFilter* filter) = 0;
   virtual void RemoveFilter(IPC::ChannelProxy::MessageFilter* filter) = 0;
+
+  // Called by a RenderWidget when it is hidden or restored.
+  virtual void WidgetHidden() = 0;
+  virtual void WidgetRestored() = 0;
 };
 
 // The RenderThread class represents a background thread where RenderView
 // instances live.  The RenderThread supports an API that is used by its
 // consumer to talk indirectly to the RenderViews and supporting objects.
 // Likewise, it provides an API for the RenderViews to talk back to the main
 // process (i.e., their corresponding TabContents).
 //
 // Most of the communication occurs in the form of IPC messages.  They are
 // routed to the RenderThread according to the routing IDs of the messages.
@@ skipping 10 matching lines @@
   // Returns the one render thread for this process.  Note that this should only
   // be accessed when running on the render thread itself
   static RenderThread* current();
 
   // Overridden from RenderThreadBase.
   virtual bool Send(IPC::Message* msg) {
     return ChildThread::Send(msg);
   }
 
   virtual void AddRoute(int32 routing_id, IPC::Channel::Listener* listener) {
+    widget_count_++;
     return ChildThread::AddRoute(routing_id, listener);
   }
   virtual void RemoveRoute(int32 routing_id) {
+    widget_count_--;
     return ChildThread::RemoveRoute(routing_id);
   }
 
   virtual void AddFilter(IPC::ChannelProxy::MessageFilter* filter);
   virtual void RemoveFilter(IPC::ChannelProxy::MessageFilter* filter);
 
+  virtual void WidgetHidden();
+  virtual void WidgetRestored();
+
   VisitedLinkSlave* visited_link_slave() const {
     return visited_link_slave_.get();
   }
 
   UserScriptSlave* user_script_slave() const {
     return user_script_slave_.get();
   }
 
   AppCacheDispatcher* appcache_dispatcher() const {
     return appcache_dispatcher_.get();
@@ skipping 55 matching lines @@
   void OnPurgePluginListCache();
 
   // Gather usage statistics from the in-memory cache and inform our host.
   // These functions should be call periodically so that the host can make
   // decisions about how to allocation resources using current information.
   void InformHostOfCacheStats();
 
   // We initialize WebKit as late as possible.
   void EnsureWebKitInitialized();
 
+  // A task we invoke periodically to assist with idle cleanup.
+  void IdleHandler();
+
   // These objects live solely on the render thread.
-  scoped_ptr<ScopedRunnableMethodFactory<RenderThread> > cache_stats_factory_;
+  scoped_ptr<ScopedRunnableMethodFactory<RenderThread> > task_factory_;
   scoped_ptr<VisitedLinkSlave> visited_link_slave_;
   scoped_ptr<UserScriptSlave> user_script_slave_;
   scoped_ptr<RenderDnsMaster> dns_master_;
   scoped_ptr<AppCacheDispatcher> appcache_dispatcher_;
   scoped_refptr<DevToolsAgentFilter> devtools_agent_filter_;
   scoped_ptr<RendererHistogramSnapshots> histogram_snapshots_;
   scoped_ptr<RendererWebKitClientImpl> webkit_client_;
 
   scoped_refptr<DBMessageFilter> db_message_filter_;
 
 #if defined(OS_POSIX)
   scoped_refptr<IPC::ChannelProxy::MessageFilter>
       suicide_on_channel_error_filter_;
 #endif
 
   // If true, then a GetPlugins call is allowed to rescan the disk.
   bool plugin_refresh_allowed_;
 
+  // Is there a pending task for doing CacheStats.
+  bool cache_stats_task_pending_;
+
+  // The count of RenderWidgets running through this thread.
+  int widget_count_;
+
+  // The count of hidden RenderWidgets running through this thread.
+  int hidden_widget_count_;
+
+  // The current value of the idle notification timer delay.
+  double idle_notification_delay_in_s_;
+
   DISALLOW_COPY_AND_ASSIGN(RenderThread);
 };
 
 #endif  // CHROME_RENDERER_RENDER_THREAD_H_