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

chrome/browser/prerender/prerender_manager.cc

Index: chrome/browser/prerender/prerender_manager.cc
===================================================================
--- chrome/browser/prerender/prerender_manager.cc	(revision 72357)
+++ chrome/browser/prerender/prerender_manager.cc	(working copy)
@@ -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/prerender/prerender_contents.h"
@@ -30,7 +31,8 @@
     : profile_(profile),
       max_prerender_age_(base::TimeDelta::FromSeconds(
           kDefaultMaxPrerenderAgeSeconds)),
-      max_elements_(kDefaultMaxPrerenderElements) {
+      max_elements_(kDefaultMaxPrerenderElements),
+      mode_(PRERENDER_MODE_ENABLED) {
 }
 
 PrerenderManager::~PrerenderManager() {
@@ -108,6 +110,9 @@
   if (!title.empty())
     tc->UpdateTitle(rvh, pc->page_id(), UTF16ToWideHack(title));
 
+  if (pc->has_stopped_loading())
+    tc->DidStopLoading();
+
   return true;
 }
 
@@ -139,3 +144,16 @@
     const std::vector<GURL>& alias_urls) {
   return new PrerenderContents(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;
+  }
+}