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

chrome/browser/tab_contents/tab_contents.cc

 // 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.
 
 #include "chrome/browser/tab_contents/tab_contents.h"
 
 #include <cmath>
 
 #include "base/auto_reset.h"
 #include "base/metrics/histogram.h"
@@ skipping 357 matching lines @@
       autofill_manager_(),
       plugin_installer_(),
       bookmark_drag_(NULL),
       ALLOW_THIS_IN_INITIALIZER_LIST(fav_icon_helper_(this)),
       is_loading_(false),
       crashed_status_(base::TERMINATION_STATUS_STILL_RUNNING),
       crashed_error_code_(0),
       waiting_for_response_(false),
       max_page_id_(-1),
       current_load_start_(),
+      pplt_load_start_(),
       load_state_(net::LOAD_STATE_IDLE),
       load_state_host_(),
       upload_size_(0),
       upload_position_(0),
       received_page_title_(false),
       is_starred_(false),
       contents_mime_type_(),
       encoding_(),
       blocked_contents_(NULL),
       all_contents_blocked_(false),
@@ skipping 1259 matching lines @@
 
   ProvisionalLoadDetails details(
       is_main_frame,
       controller_.IsURLInPageNavigation(validated_url),
       validated_url, std::string(), false, is_error_page, frame_id);
   NotificationService::current()->Notify(
       NotificationType::FRAME_PROVISIONAL_LOAD_START,
       Source<NavigationController>(&controller_),
       Details<ProvisionalLoadDetails>(&details));
   if (is_main_frame) {
+    // Record the beginning of a new PPLT navigation.
+    pplt_load_start_ = base::TimeTicks::Now();
+
     // If we're displaying a network error page do not reset the content
     // settings delegate's cookies so the user has a chance to modify cookie
     // settings.
     if (!is_error_page)
       content_settings_delegate_->ClearCookieSpecificContentSettings();
     content_settings_delegate_->ClearGeolocationContentSettings();
 
     // Check if the URL we are about to load has been prerendered by any chance,
     // and use it if possible.
     MaybeUsePreloadedPage(url);
@@ skipping 1140 matching lines @@
     details.reset(new LoadNotificationDetails(
         entry->virtual_url(),
         entry->transition_type(),
         elapsed,
         &controller_,
         controller_.GetCurrentEntryIndex()));
   }
 
   SetIsLoading(false, details.get());
 
+  // Compute the PPLT metric and report it in a histogram, if needed.
+  PrerenderManager* pm = profile()->GetPrerenderManager();

[cbentzel, 2011/01/26 19:38:36]

Can you move this into PrerenderManager or PrerenderContents?

[tburkard, 2011/01/26 20:05:50]

Done.

+  if (pm != NULL && !pplt_load_start_.is_null() &&
+      (pm->mode() == PrerenderManager::kExperimentControlGroup ||
+       pm->mode() == PrerenderManager::kExperimentPrerenderGroup)) {
+    base::TimeDelta elapsed = base::TimeTicks::Now() - pplt_load_start_;
+    if (pm->mode() == PrerenderManager::kExperimentControlGroup) {
+      UMA_HISTOGRAM_TIMES("PLT.PerceivedPageLoadTime_PrerenderControl",
+                          elapsed);
+    } else {
+      UMA_HISTOGRAM_TIMES("PLT.PerceivedPageLoadTime_PrerenderTreatment",
+                          elapsed);
+    }
+  }
+
+  // Reset the PPLT metric.
+  pplt_load_start_ = base::TimeTicks();
+
   // Notify observers about navigation.
   FOR_EACH_OBSERVER(WebNavigationObserver, web_navigation_observers_,
                     DidStopLoading());
 }
 
 void TabContents::DidChangeLoadProgress(double progress) {
   if (delegate())
     delegate()->LoadProgressChanged(progress);
 }
 
@@ skipping 559 matching lines @@
 }
 
 void TabContents::CreateViewAndSetSizeForRVH(RenderViewHost* rvh) {
   RenderWidgetHostView* rwh_view = view()->CreateViewForWidget(rvh);
   rwh_view->SetSize(view()->GetContainerSize());
 }
 
 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;
 }