[Prerender] first contentful paint histograms.

chrome/browser/prerender/prerender_manager.h

 // 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_PRERENDER_PRERENDER_MANAGER_H_
 #define CHROME_BROWSER_PRERENDER_PRERENDER_MANAGER_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 54 matching lines @@
 namespace prerender {
 
 namespace test_utils {
 class PrerenderInProcessBrowserTest;
 }
 
 class PrerenderHandle;
 class PrerenderHistory;
 class PrerenderLocalPredictor;
 
+// Observer interface for PrerenderManager events.
+class PrerenderManagerObserver {
+ public:
+  // Called from the UI thread.
+  virtual void OnFirstContentfulPaint() = 0;
+};
+
 // PrerenderManager is responsible for initiating and keeping prerendered
 // views of web pages. All methods must be called on the UI thread unless
 // indicated otherwise.
 class PrerenderManager : public content::NotificationObserver,
                          public content::RenderProcessHostObserver,
                          public KeyedService,
                          public MediaCaptureDevicesDispatcher::Observer {
  public:
   // NOTE: New values need to be appended, since they are used in histograms.
   enum PrerenderManagerMode {
@@ skipping 127 matching lines @@
                                       bool is_main_resource,
                                       bool is_redirect,
                                       bool is_no_store);
 
   // Called when a NoStatePrefetch resource has been loaded. This is called only
   // once per resource, when all redirects have been resolved.
   void RecordPrefetchRedirectCount(Origin origin,
                                    bool is_main_resource,
                                    int redirect_count);
 
-  // Records the time to first contentful paint.
-  // Must not be called for prefetch loads (which are never rendered anyway).
-  // |is_no_store| must be true if the main resource has a "no-store" cache
-  // control HTTP header.
-  void RecordFirstContentfulPaint(const GURL& url,
-                                  bool is_no_store,
-                                  base::TimeDelta time);
+  // Records the time to first contentful paint for loads that previously had a
+  // no state prefetch load.  Must not be called for prefetch loads themselves
+  // (which are never rendered anyway).  |is_no_store| must be true if the main
+  // resource has a "no-store" cache control HTTP header.
+  void RecordNoStateFirstContentfulPaint(const GURL& url,
+                                         bool is_no_store,
+                                         base::TimeDelta time);
+
+  // Records the perceived first contentful paint time for a prerendered page,
+  // analogous to |RecordPerceivedPageLoadTime|. The FCP ticks is in absolute
+  // time; this has the disadvantage that the histogram will mix browser and
+  // renderer ticks, but there seems to be no way around that.
+  void RecordPerceivedFirstContentfulPaint(content::WebContents* web_contents,
+                                           base::TimeTicks ticks,
+                                           bool was_hidden);
 
   static PrerenderManagerMode GetMode();
   static void SetMode(PrerenderManagerMode mode);
   static bool IsPrerenderingPossible();
   static bool ActuallyPrerendering();
   static bool IsControlGroup();
   static bool IsNoUseGroup();
   static bool IsNoStatePrefetch();
 
   // Query the list of current prerender pages to see if the given web contents
@@ skipping 83 matching lines @@
   Profile* profile() const { return profile_; }
 
   // Return current time and ticks with ability to mock the clock out for
   // testing.
   base::Time GetCurrentTime() const;
   base::TimeTicks GetCurrentTimeTicks() const;
   void SetClockForTesting(std::unique_ptr<base::SimpleTestClock> clock);
   void SetTickClockForTesting(
       std::unique_ptr<base::SimpleTestTickClock> tick_clock);
 
+  void DisablePageLoadMetricsObserverForTesting() {
+    page_load_metric_observer_disabled_ = true;
+  }
+
+  bool PageLoadMetricsObserverDisabledForTesting() const {
+    return page_load_metric_observer_disabled_;
+  }
+
+  void AddObserver(std::unique_ptr<PrerenderManagerObserver> observer);
+
   // Notification that a prerender has completed and its bytes should be
   // recorded.
   void RecordNetworkBytes(Origin origin, bool used, int64_t prerender_bytes);
 
   // Add to the running tally of bytes transferred over the network for this
   // profile if prerendering is currently enabled.
   void AddProfileNetworkBytesIfEnabled(int64_t bytes);
 
   // Registers a new ProcessHost performing a prerender. Called by
   // PrerenderContents.
@@ skipping 261 matching lines @@
   // The value of profile_network_bytes_ that was last recorded.
   int64_t last_recorded_profile_network_bytes_;
 
   // Set of process hosts being prerendered.
   using PrerenderProcessSet = std::set<content::RenderProcessHost*>;
   PrerenderProcessSet prerender_process_hosts_;
 
   std::unique_ptr<base::Clock> clock_;
   std::unique_ptr<base::TickClock> tick_clock_;
 
+  bool page_load_metric_observer_disabled_;
+
+  std::vector<std::unique_ptr<PrerenderManagerObserver>> observers_;
+
   base::WeakPtrFactory<PrerenderManager> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(PrerenderManager);
 };
 
 }  // namespace prerender
 
 #endif  // CHROME_BROWSER_PRERENDER_PRERENDER_MANAGER_H_