Adding histograms showing fraction of page load times

chrome/browser/net/cache_stats.h

Index: chrome/browser/net/cache_stats.h
===================================================================
--- chrome/browser/net/cache_stats.h	(revision 0)
+++ chrome/browser/net/cache_stats.h	(revision 0)
@@ -0,0 +1,110 @@
+// 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 CHROME_BROWSER_NET_CACHE_STATS_H_
+#define CHROME_BROWSER_NET_CACHE_STATS_H_
+#pragma once
+
+#include <map>
+#include <string>
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/hash_tables.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/singleton.h"
+#include "base/message_loop.h"
+#include "base/time.h"
+#include "content/public/browser/render_view_host_observer.h"
+#include "net/base/network_delegate.h"
+
+class TabContents;
+
+namespace base {
+class Histogram;
+}
+
+namespace net {
+class URLRequest;
+}
+
+namespace chrome_browser_net {
+
+// This class collects UMA stats about cache performance.  It is a singleton
+// and lives on the IO thread.
+
+class CacheStats : public MessageLoop::DestructionObserver {
+ public:
+  enum TabEvent {
+    SPINNER_START,
+    SPINNER_STOP,
+    RENDERER_DESTROY
+  };
+  static CacheStats* GetInstance();
+  void OnCacheWaitStateChange(const net::URLRequest& request,
+                              net::NetworkDelegate::CacheWaitState state);
+  void OnTabEvent(std::pair<int, int> render_view_id, TabEvent event);
+  virtual void WillDestroyCurrentMessageLoop() OVERRIDE;
+  virtual ~CacheStats();
+
+ private:
+  friend struct DefaultSingletonTraits<CacheStats>;
+  struct TabLoadStats;
+  typedef std::map< std::pair<int, int>, TabLoadStats*> TabLoadStatsMap;
+
+  CacheStats();
+  // Gets TabLoadStats for a given render view.
+  TabLoadStats* GetTabLoadStats(std::pair<int, int> render_view_id);
+  // Deletes TabLoadStats no longer needed for a render view.
+  void RemoveTabLoadStats(std::pair<int, int> render_view_id);
+  // Sets a timer for a given tab to collect stats.  timer_index indicates
+  // how many times stats have been collected since the navigation has started
+  // for this tab.
+  void ScheduleTimer(TabLoadStats* stats, int timer_index);
+  // The callback when a timer fires to collect stats again.
+  void TimerCb(TabLoadStats* stats, int timer_index);
+  // Helper function to put the current set of cache statistics into an UMA
+  // histogram.
+  void RecordCacheFractionHistogram(base::TimeDelta elapsed,
+                                    base::TimeDelta cache_time,
+                                    bool is_load_done);
+
+  TabLoadStatsMap tab_load_stats_;
+  std::vector<base::Histogram*> final_histograms_;
+  std::vector<base::Histogram*> intermediate_histograms_;
+  bool registered_message_loop_destruction_observer_;
+};
+
+// Helper class observing all RenderViewHosts, notifying CacheStats
+// whenever the spinner starts or stops for a given tab, and when a renderer
+// is no longer used.
+
+class CacheStatsRenderViewHostObserver :
+      public content::RenderViewHostObserver {

[mmenke, 2012/07/20 18:37:44]

Fix indent.  Also, I believe the more common style is to put the colon on the
same line as public.

[tburkard, 2012/07/20 19:36:42]

Done.

+ public:
+  explicit CacheStatsRenderViewHostObserver(content::RenderViewHost* host);
+
+ protected:
+  virtual ~CacheStatsRenderViewHostObserver();
+  virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
+
+ private:
+  // Calls into CacheStats to notify that a reportable event has occurred
+  // for the tab being observed.
+  void NotifyCacheStats(CacheStats::TabEvent event);
+  void OnDidStartProvisionalLoadForFrame(
+      int64 frame_id,
+      bool is_main_frame,
+      const GURL& opener_url,
+      const GURL& url);
+  void OnDidStopLoading();
+
+  CacheStats* cache_stats_;
+  std::pair<int, int> render_view_id_;
+  bool is_loading_;
+};
+
+}  // namespace chrome_browser_net
+
+#endif  // CHROME_BROWSER_NET_CACHE_STATS_H_