Add a histogram for renderer memory usage.

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 13 matching lines @@
 
 class SkBitmap;
 struct ViewMsg_New_Params;
 
 namespace WebKit {
 class WebMediaStreamCenter;
 class WebMediaStreamCenterClient;
 }
 
 namespace base {
+class Histogram;
 class MessageLoopProxy;
 class Thread;
 
 #if defined(OS_WIN)
 namespace win {
 class ScopedCOMInitializer;
 }
 #endif
 }
 
@@ skipping 215 matching lines @@
     // displaying 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) const;
 
+    // Custom histograms maintained by the HistogramCustomizer itself.
+    base::Histogram* memory_renderer_used();
+
    private:
     friend class RenderThreadImplUnittest;
 
     // 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);
 
     // The current common host of the RenderViews; empty string if there is no
     // common host.
     std::string common_host_;
     // The corresponding suffix.
     std::string common_host_histogram_suffix_;
     // Set of histograms for which we want to produce a custom histogram if
     // possible.
     std::set<std::string> custom_histograms_;
 
+    // Custom histograms maintained by this object.
+    base::Histogram* memory_renderer_used_;
+
     DISALLOW_COPY_AND_ASSIGN(HistogramCustomizer);
   };
 
   HistogramCustomizer* histogram_customizer() {
     return &histogram_customizer_;
   }
 
  private:
   virtual bool OnControlMessageReceived(const IPC::Message& msg) OVERRIDE;
 
@@ skipping 77 matching lines @@
   scoped_ptr<AudioRendererMixerManager> audio_renderer_mixer_manager_;
 
   HistogramCustomizer histogram_customizer_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderThreadImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_RENDER_THREAD_IMPL_H_