Add Perceived PageLoad Time (PPLT) metrics for Prerender Experiments.

BUG=None
Test=None

Review URL: http://codereview.chromium.org/6263014

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@72714 0039d316-1c4b-4281-b951-d872f2087c98

9 files changed, 146 insertions, 7 deletions

diff --git a/chrome/browser/prerender/prerender_contents.cc b/chrome/browser/prerender/prerender_contents.cc
index bd84b8e..c20a906 100644
--- a/chrome/browser/prerender/prerender_contents.cc
+++ b/chrome/browser/prerender/prerender_contents.cc
@@ -37,7 +37,8 @@ PrerenderContents::PrerenderContents(PrerenderManager* prerender_manager,
       render_view_host_(NULL),
       prerender_url_(url),
       profile_(profile),
-      page_id_(0) {
+      page_id_(0),
+      has_stopped_loading_(false) {
   DCHECK(prerender_manager != NULL);
   AddAliasURL(prerender_url_);
   for (std::vector<GURL>::const_iterator it = alias_urls.begin();
@@ -279,3 +280,7 @@ bool PrerenderContents::MatchesURL(const GURL& url) const {
   return std::find(alias_urls_.begin(), alias_urls_.end(), url)
       != alias_urls_.end();
 }
+
+void PrerenderContents::DidStopLoading() {
+  has_stopped_loading_ = true;
+}
diff --git a/chrome/browser/prerender/prerender_contents.h b/chrome/browser/prerender/prerender_contents.h
index 4f55aba..9ac0929 100644
--- a/chrome/browser/prerender/prerender_contents.h
+++ b/chrome/browser/prerender/prerender_contents.h
@@ -67,6 +67,7 @@ class PrerenderContents : public RenderViewHostDelegate,
   }
   string16 title() const { return title_; }
   int32 page_id() const { return page_id_; }
+  bool has_stopped_loading() const { return has_stopped_loading_; }
 
   // Indicates whether this prerendered page can be used for the provided
   // URL, i.e. whether there is a match.
@@ -91,6 +92,7 @@ class PrerenderContents : public RenderViewHostDelegate,
                                     IPC::Message* reply_msg,
                                     bool* did_suppress_message);
   virtual void Close(RenderViewHost* render_view_host);
+  virtual void DidStopLoading();
   virtual RendererPreferences GetRendererPrefs(Profile* profile) const;
 
   // RenderViewHostDelegate::View
@@ -206,6 +208,8 @@ class PrerenderContents : public RenderViewHostDelegate,
   // such as HTTP redirects or javascript redirects.
   std::vector<GURL> alias_urls_;
 
+  bool has_stopped_loading_;
+
   DISALLOW_COPY_AND_ASSIGN(PrerenderContents);
 };
 
diff --git a/chrome/browser/prerender/prerender_manager.cc b/chrome/browser/prerender/prerender_manager.cc
index cc5b683..0459058 100644
--- a/chrome/browser/prerender/prerender_manager.cc
+++ b/chrome/browser/prerender/prerender_manager.cc
@@ -5,6 +5,7 @@
 #include "chrome/browser/prerender/prerender_manager.h"
 
 #include "base/logging.h"
+#include "base/metrics/histogram.h"
 #include "base/time.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/browser_thread.h"
@@ -32,7 +33,8 @@ PrerenderManager::PrerenderManager(Profile* profile)
       max_prerender_age_(base::TimeDelta::FromSeconds(
           kDefaultMaxPrerenderAgeSeconds)),
       max_elements_(kDefaultMaxPrerenderElements),
-      prerender_contents_factory_(PrerenderContents::CreateFactory()) {
+      prerender_contents_factory_(PrerenderContents::CreateFactory()),
+      mode_(PRERENDER_MODE_ENABLED) {
 }
 
 PrerenderManager::~PrerenderManager() {
@@ -115,6 +117,9 @@ bool PrerenderManager::MaybeUsePreloadedPage(TabContents* tc, const GURL& url) {
   if (!title.empty())
     tc->UpdateTitle(rvh, pc->page_id(), UTF16ToWideHack(title));
 
+  if (pc->has_stopped_loading())
+    tc->DidStopLoading();
+
   return true;
 }
 
@@ -148,6 +153,19 @@ PrerenderContents* PrerenderManager::CreatePrerenderContents(
       this, profile_, url, alias_urls);
 }
 
+void PrerenderManager::RecordPerceivedPageLoadTime(base::TimeDelta pplt) {
+  switch(mode_) {
+    case PRERENDER_MODE_EXPERIMENT_CONTROL_GROUP:
+      UMA_HISTOGRAM_TIMES("PLT.PerceivedPageLoadTime_PrerenderControl", pplt);
+      break;
+    case PRERENDER_MODE_EXPERIMENT_PRERENDER_GROUP:
+      UMA_HISTOGRAM_TIMES("PLT.PerceivedPageLoadTime_PrerenderTreatment", pplt);
+      break;
+    default:
+      break;
+  }
+}
+
 PrerenderContents* PrerenderManager::FindEntry(const GURL& url) {
   for (std::list<PrerenderContentsData>::iterator it = prerender_list_.begin();
        it != prerender_list_.end();
diff --git a/chrome/browser/prerender/prerender_manager.h b/chrome/browser/prerender/prerender_manager.h
index d23cbe5e..62967d8 100644
--- a/chrome/browser/prerender/prerender_manager.h
+++ b/chrome/browser/prerender/prerender_manager.h
@@ -22,6 +22,13 @@ class TabContents;
 // views of webpages.
 class PrerenderManager : public base::RefCounted<PrerenderManager> {
  public:
+  enum PrerenderManagerMode {
+    PRERENDER_MODE_DISABLED,
+    PRERENDER_MODE_ENABLED,
+    PRERENDER_MODE_EXPERIMENT_CONTROL_GROUP,
+    PRERENDER_MODE_EXPERIMENT_PRERENDER_GROUP
+  };
+
   // Owned by a Profile object for the lifetime of the profile.
   explicit PrerenderManager(Profile* profile);
 
@@ -45,6 +52,8 @@ class PrerenderManager : public base::RefCounted<PrerenderManager> {
   // Returns NULL if the specified URL has not been prerendered.
   PrerenderContents* GetEntry(const GURL& url);
 
+  void RecordPerceivedPageLoadTime(base::TimeDelta pplt);
+
   base::TimeDelta max_prerender_age() const { return max_prerender_age_; }
   void set_max_prerender_age(base::TimeDelta td) { max_prerender_age_ = td; }
   unsigned int max_elements() const { return max_elements_; }
@@ -91,6 +100,8 @@ class PrerenderManager : public base::RefCounted<PrerenderManager> {
 
   scoped_ptr<PrerenderContents::Factory> prerender_contents_factory_;
 
+  PrerenderManagerMode mode_;
+
   DISALLOW_COPY_AND_ASSIGN(PrerenderManager);
 };
 
diff --git a/chrome/browser/prerender/prerender_plt_recorder.cc b/chrome/browser/prerender/prerender_plt_recorder.cc
new file mode 100644
index 0000000..60b5da9
--- /dev/null
+++ b/chrome/browser/prerender/prerender_plt_recorder.cc
@@ -0,0 +1,47 @@
+// Copyright (c) 2010 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.
+
+#include "chrome/browser/prerender/prerender_plt_recorder.h"
+
+#include "base/time.h"
+#include "chrome/browser/prerender/prerender_manager.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/tab_contents/tab_contents.h"
+#include "chrome/common/render_messages.h"
+
+PrerenderPLTRecorder::PrerenderPLTRecorder(TabContents* tab_contents)
+    : tab_contents_(tab_contents),
+      pplt_load_start_() {
+
+}
+
+PrerenderPLTRecorder::~PrerenderPLTRecorder() {
+}
+
+bool PrerenderPLTRecorder::OnMessageReceived(const IPC::Message& message) {
+  IPC_BEGIN_MESSAGE_MAP(PrerenderPLTRecorder, message)
+      IPC_MESSAGE_HANDLER(ViewHostMsg_DidStartProvisionalLoadForFrame,
+                          OnDidStartProvisionalLoadForFrame)
+  IPC_END_MESSAGE_MAP()
+  return false;
+}
+
+void PrerenderPLTRecorder::OnDidStartProvisionalLoadForFrame(int64 frame_id,
+                                                             bool is_main_frame,
+                                                             const GURL& url) {
+  if (is_main_frame) {
+    // Record the beginning of a new PPLT navigation.
+    pplt_load_start_ = base::TimeTicks::Now();
+  }
+}
+
+void PrerenderPLTRecorder::DidStopLoading() {
+  // Compute the PPLT metric and report it in a histogram, if needed.
+  PrerenderManager* pm = tab_contents_->profile()->GetPrerenderManager();
+  if (pm != NULL && !pplt_load_start_.is_null())
+    pm->RecordPerceivedPageLoadTime(base::TimeTicks::Now() - pplt_load_start_);
+
+  // Reset the PPLT metric.
+  pplt_load_start_ = base::TimeTicks();
+}
diff --git a/chrome/browser/prerender/prerender_plt_recorder.h b/chrome/browser/prerender/prerender_plt_recorder.h
new file mode 100644
index 0000000..bf1e94e
--- /dev/null
+++ b/chrome/browser/prerender/prerender_plt_recorder.h
@@ -0,0 +1,48 @@
+// Copyright (c) 2011 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_PRERENDER_PRERENDER_PLT_RECORDER_H_
+#define CHROME_BROWSER_PRERENDER_PRERENDER_PLT_RECORDER_H_
+#pragma once
+
+#include <list>
+#include <vector>
+
+#include "base/scoped_ptr.h"
+#include "base/time.h"
+#include "chrome/browser/tab_contents/web_navigation_observer.h"
+#include "googleurl/src/gurl.h"
+
+class PrerenderContents;
+class Profile;
+class TabContents;
+
+// PrerenderPLTRecorder is responsible for recording perceived pageload times
+// to compare PLT's with prerendering enabled and disabled.
+class PrerenderPLTRecorder : public WebNavigationObserver {
+ public:
+  explicit PrerenderPLTRecorder(TabContents* tab_contents);
+  virtual ~PrerenderPLTRecorder();
+
+  // WebNavigationObserver implementation.
+  virtual bool OnMessageReceived(const IPC::Message& message);
+
+  // Message handler.
+  void OnDidStartProvisionalLoadForFrame(int64 frame_id,
+                                         bool main_frame,
+                                         const GURL& url);
+
+  virtual void DidStopLoading();
+
+ private:
+  TabContents* tab_contents_;
+
+  // System time at which the current load was started for the purpose of
+  // the perceived page load time (PPLT).
+  base::TimeTicks pplt_load_start_;
+
+  DISALLOW_COPY_AND_ASSIGN(PrerenderPLTRecorder);
+};
+
+#endif  // CHROME_BROWSER_PRERENDER_PRERENDER_PLT_RECORDER_H_
diff --git a/chrome/browser/tab_contents/tab_contents.cc b/chrome/browser/tab_contents/tab_contents.cc
index 7d1703e..370ff80e 100644
--- a/chrome/browser/tab_contents/tab_contents.cc
+++ b/chrome/browser/tab_contents/tab_contents.cc
@@ -52,6 +52,7 @@
 #include "chrome/browser/plugin_installer_infobar_delegate.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/prerender/prerender_manager.h"
+#include "chrome/browser/prerender/prerender_plt_recorder.h"
 #include "chrome/browser/printing/print_preview_tab_controller.h"
 #include "chrome/browser/printing/print_view_manager.h"
 #include "chrome/browser/profiles/profile.h"
@@ -367,6 +368,7 @@ TabContents::TabContents(Profile* profile,
       autocomplete_history_manager_(),
       autofill_manager_(),
       plugin_installer_(),
+      prerender_plt_recorder_(),
       bookmark_drag_(NULL),
       ALLOW_THIS_IN_INITIALIZER_LIST(fav_icon_helper_(this)),
       is_loading_(false),
@@ -472,6 +474,8 @@ TabContents::TabContents(Profile* profile,
   AddNavigationObserver(autofill_manager_.get());
   autocomplete_history_manager_.reset(new AutocompleteHistoryManager(this));
   AddNavigationObserver(autocomplete_history_manager_.get());
+  prerender_plt_recorder_.reset(new PrerenderPLTRecorder(this));
+  AddNavigationObserver(prerender_plt_recorder_.get());
   AddNavigationObserver(&fav_icon_helper_);
   AddNavigationObserver(printing_.get());
 }
@@ -3393,12 +3397,8 @@ void TabContents::CreateViewAndSetSizeForRVH(RenderViewHost* rvh) {
 bool TabContents::MaybeUsePreloadedPage(const GURL& url) {
   PrerenderManager* pm = profile()->GetPrerenderManager();
   if (pm != NULL) {
-    if (pm->MaybeUsePreloadedPage(this, url)) {
-      // TODO(tburkard): If the preloaded page has not finished preloading
-      // yet, we should not do this.
-      DidStopLoading();
+    if (pm->MaybeUsePreloadedPage(this, url))
       return true;
-    }
   }
   return false;
 }
diff --git a/chrome/browser/tab_contents/tab_contents.h b/chrome/browser/tab_contents/tab_contents.h
index a40edfb..b0af381 100644
--- a/chrome/browser/tab_contents/tab_contents.h
+++ b/chrome/browser/tab_contents/tab_contents.h
@@ -68,6 +68,7 @@ class OmniboxSearchHint;
 class PluginInstallerInfoBarDelegate;
 class Profile;
 class PrerenderManager;
+class PrerenderPLTRecorder;
 struct RendererPreferences;
 class RenderViewHost;
 class SessionStorageNamespace;
@@ -1124,6 +1125,9 @@ class TabContents : public PageNavigator,
   // PluginInstallerInfoBarDelegate, lazily created.
   scoped_ptr<PluginInstallerInfoBarDelegate> plugin_installer_;
 
+  // Prerender PageLoadTime Recorder.
+  scoped_ptr<PrerenderPLTRecorder> prerender_plt_recorder_;
+
   // TabContentsSSLHelper, lazily created.
   scoped_ptr<TabContentsSSLHelper> ssl_helper_;
 
diff --git a/chrome/chrome_browser.gypi b/chrome/chrome_browser.gypi
index c6f329a..b2d44d1 100644
--- a/chrome/chrome_browser.gypi
+++ b/chrome/chrome_browser.gypi
@@ -2082,6 +2082,8 @@
         'browser/prerender/prerender_contents.h',
         'browser/prerender/prerender_manager.cc',
         'browser/prerender/prerender_manager.h',
+        'browser/prerender/prerender_plt_recorder.cc',
+        'browser/prerender/prerender_plt_recorder.h',
         'browser/prerender/prerender_resource_handler.h',
         'browser/prerender/prerender_resource_handler.cc',
         'browser/printing/print_dialog_gtk.cc',