Per-host V8 histograms.

content/renderer/render_thread_impl.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 CONTENT_RENDERER_RENDER_THREAD_IMPL_H_
 #define CONTENT_RENDERER_RENDER_THREAD_IMPL_H_
 
 #include <set>
 #include <string>
 #include <vector>
@@ skipping 220 matching lines @@
   WebGraphicsContext3DCommandBufferImpl* GetGpuVDAContext3D();
 
   // Handle loss of the shared GpuVDAContext3D context above.
   static void OnGpuVDAContextLoss();
 
   // AudioRendererMixerManager instance which manages renderer side mixer
   // instances shared based on configured audio parameters.  Lazily created on
   // first call.
   content::AudioRendererMixerManager* GetAudioRendererMixerManager();
 
+  // Called when a top frame of a RenderView navigates. This function updates
+  // RenderViewThread's information about whether all RenderViews are displaying

[Charlie Reis, 2012/08/22 23:09:59]

nit: RenderViewThread -> RenderThreadImpl?

[marja, 2012/08/23 14:15:00]

Done.

+  // a page from the same host. |host| is the host where a RenderView navigated,
+  // and |view_count| is the number of RenderViews in this process.
+  void RenderViewNavigatedToHost(const std::string& host, size_t view_count);
+
+  // Used for customizing some histograms if all RenderViews share the same
+  // host. Returns the current custom histogram name to use for
+  // |histogram_name|, or |histogram_name| if it shouldn't be customized.
+  std::string ConvertToCustomHistogramName(const char* histogram_name);
+
  private:
   virtual bool OnControlMessageReceived(const IPC::Message& msg) OVERRIDE;
 
   void Init();
 
   void OnSetZoomLevelForCurrentURL(const std::string& host, double zoom_level);
   void OnSetCSSColors(const std::vector<CSSColors::CSSColorMapping>& colors);
   void OnCreateNewView(const ViewMsg_New_Params& params);
   void OnTransferBitmap(const SkBitmap& bitmap, int resource_id);
   void OnPurgePluginListCache(bool reload_pages);
   void OnNetworkStateChanged(bool online);
   void OnGetAccessibilityTree();
   void OnTempCrashWithData(const GURL& data);
 
   void IdleHandlerInForegroundTab();
 
+  // Used for updating the information on which is the common host which all
+  // RenderView's share (if any). If there is no common host, this function is
+  // called with an empty string.
+  void SetCommonHost(const std::string& host);
+
+  // For initializing information about which histograms should be customized
+  // per host.
+  void InitializeCustomHistograms();
+
   // These objects live solely on the render thread.
   scoped_ptr<AppCacheDispatcher> appcache_dispatcher_;
   scoped_ptr<DomStorageDispatcher> dom_storage_dispatcher_;
   scoped_ptr<IndexedDBDispatcher> main_thread_indexed_db_dispatcher_;
   scoped_ptr<RendererWebKitPlatformSupportImpl> webkit_platform_support_;
   scoped_ptr<content::old::BrowserPluginChannelManager>
       browser_plugin_channel_manager_;
 
   // Used on the render thread and deleted by WebKit at shutdown.
   content::MediaStreamCenter* media_stream_center_;
@@ skipping 44 matching lines @@
   scoped_ptr<content::old::BrowserPluginRegistry> browser_plugin_registry_;
 
   ObserverList<content::RenderProcessObserver> observers_;
 
   class GpuVDAContextLostCallback;
   scoped_ptr<GpuVDAContextLostCallback> context_lost_cb_;
   scoped_ptr<WebGraphicsContext3DCommandBufferImpl> gpu_vda_context3d_;
 
   scoped_ptr<content::AudioRendererMixerManager> audio_renderer_mixer_manager_;
 
+  // For producing custom histograms if all RenderViews share the same host.

[Charlie Reis, 2012/08/22 23:09:59]

Can you say a bit more?  e.g., that the histogram names in the set will be
customized with a site-specific suffix if the process is only used for pages
from a set of known sites?

[marja, 2012/08/23 14:15:00]

Done.

+  std::string common_host_;
+  std::string custom_page_;

[Charlie Reis, 2012/08/22 23:09:59]

custom_page_ doesn't reveal much about what it's for.  Maybe
common_host_histogram_suffix_?

[marja, 2012/08/23 14:15:00]

Done.

+  std::set<std::string> custom_histograms_;
+
   DISALLOW_COPY_AND_ASSIGN(RenderThreadImpl);
 };
 
 #endif  // CONTENT_RENDERER_RENDER_THREAD_IMPL_H_