[Prerender] first contentful paint histograms.

chrome/browser/prerender/prerender_manager.cc

Index: chrome/browser/prerender/prerender_manager.cc
diff --git a/chrome/browser/prerender/prerender_manager.cc b/chrome/browser/prerender/prerender_manager.cc
index dc09eb8365aa6cf03be6e0a81a023c49c3f977ab..042e24e20ffb35e2dd66396f1eb8f890431a313d 100644
--- a/chrome/browser/prerender/prerender_manager.cc
+++ b/chrome/browser/prerender/prerender_manager.cc
@@ -175,6 +175,7 @@ PrerenderManager::PrerenderManager(Profile* profile)
       last_recorded_profile_network_bytes_(0),
       clock_(new base::DefaultClock()),
       tick_clock_(new base::DefaultTickClock()),
+      page_load_metric_observer_disabled_(false),
       weak_factory_(this) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
@@ -345,8 +346,9 @@ bool PrerenderManager::MaybeUsePrerenderedPage(const GURL& url,
     return false;
   DCHECK(prerender_data->contents());
 
-  if (prerender_data->contents()->prerender_mode() != FULL_PRERENDER)
+  if (prerender_data->contents()->prerender_mode() != FULL_PRERENDER) {
     return false;
+  }
 
   std::unique_ptr<WebContents> new_web_contents = SwapInternal(
       url, web_contents, prerender_data, params->should_replace_current_entry);
@@ -588,9 +590,9 @@ void PrerenderManager::RecordPrefetchRedirectCount(Origin origin,
                                            redirect_count);
 }
 
-void PrerenderManager::RecordFirstContentfulPaint(const GURL& url,
-                                                  bool is_no_store,
-                                                  base::TimeDelta time) {
+void PrerenderManager::RecordNoStateFirstContentfulPaint(const GURL& url,
+                                                         bool is_no_store,
+                                                         base::TimeDelta time) {
   CleanUpOldNavigations(&prefetches_, base::TimeDelta::FromMinutes(30));
 
   // Compute the prefetch age.
@@ -604,8 +606,8 @@ void PrerenderManager::RecordFirstContentfulPaint(const GURL& url,
     }
   }
 
-  histograms_->RecordFirstContentfulPaint(origin, is_no_store, time,
-                                          prefetch_age);
+  histograms_->RecordNoStateFirstContentfulPaint(origin, is_no_store, time,
+                                                 prefetch_age);
 
   // Loading a prefetched URL resets the revalidation bypass. Remove the url
   // from the prefetch list for more accurate metrics.
@@ -615,6 +617,31 @@ void PrerenderManager::RecordFirstContentfulPaint(const GURL& url,
       prefetches_.end());
 }
 
+void PrerenderManager::RecordPerceivedFirstContentfulPaint(
+    content::WebContents* web_contents,
+    base::TimeDelta first_contentful_paint) {
+  for (auto& observer : observers_) {
+    observer->OnFirstContentfulPaint();
+  }
+
+  PrerenderTabHelper* tab_helper =
+      PrerenderTabHelper::FromWebContents(web_contents);
+  if (!tab_helper) {

[pasko, 2016/11/17 19:52:16]

DCHECK(tab_helper) is shorter, why not use it?

[mattcary, 2016/11/18 09:21:11]

Copied from cases like PrerenderManager::SwapInternal :/

+    NOTREACHED();
+    return;
+  }
+  base::TimeDelta perceived_delta;
+  if (tab_helper->LoadToPerceivedDelta(&perceived_delta)) {
+    histograms_->RecordPerceivedFirstContentfulPaintTime(
+        tab_helper->origin(), first_contentful_paint - perceived_delta);
+    histograms_->RecordPerceivedFirstContentfulPaintStatus(tab_helper->origin(),
+                                                           true);
+  } else {
+    histograms_->RecordPerceivedFirstContentfulPaintStatus(tab_helper->origin(),
+                                                           false);
+  }
+}
+
 // static
 PrerenderManager::PrerenderManagerMode PrerenderManager::GetMode() {
   return mode_;
@@ -1131,6 +1158,10 @@ void PrerenderManager::SetTickClockForTesting(
   tick_clock_ = std::move(tick_clock);
 }
 
+void PrerenderManager::AddObserver(std::unique_ptr<Observer> observer) {
+  observers_.push_back(std::move(observer));
+}
+
 std::unique_ptr<PrerenderContents> PrerenderManager::CreatePrerenderContents(
     const GURL& url,
     const content::Referrer& referrer,