[page_load_metrics] Get navigation_start from NavigationHandle

components/page_load_metrics/browser/metrics_web_contents_observer.h

 // Copyright 2015 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 COMPONENTS_PAGE_LOAD_METRICS_BROWSER_PAGE_LOAD_METRICS_WEB_CONTENTS_OBSERVER_H_
 #define COMPONENTS_PAGE_LOAD_METRICS_BROWSER_PAGE_LOAD_METRICS_WEB_CONTENTS_OBSERVER_H_
 
 #include "base/containers/scoped_ptr_map.h"
 #include "base/macros.h"
 #include "base/observer_list.h"
@@ skipping 177 matching lines @@
 // provisional load, until a new navigation commits or the navigation fails. It
 // also records RAPPOR/UMA about the page load.
 // MetricsWebContentsObserver manages a set of provisional PageLoadTrackers, as
 // well as a committed PageLoadTracker.
 class PageLoadTracker {
  public:
   // Caller must guarantee that the observers and embedder_interface pointers
   // outlives this class.
   PageLoadTracker(bool in_foreground,
                   PageLoadMetricsEmbedderInterface* embedder_interface,
+                  content::NavigationHandle* navigation_handle,
                   base::ObserverList<PageLoadMetricsObserver, true>* observers);
   ~PageLoadTracker();
   void Commit(content::NavigationHandle* navigation_handle);
   void WebContentsHidden();
   void WebContentsShown();
 
   // Returns true if the timing was successfully updated.
   bool UpdateTiming(const PageLoadTiming& timing);
   void RecordProvisionalEvent(ProvisionalLoadEvent event);
   void RecordCommittedEvent(CommittedLoadEvent event, bool backgrounded);
   bool HasBackgrounded();
 
  private:
   PageLoadExtraInfo GetPageLoadMetricsInfo();
   // Only valid to call post-commit.
   const GURL& GetCommittedURL();
 
   base::TimeDelta GetBackgroundDelta();
   void RecordTimingHistograms();
   void RecordRappor();
 
   bool has_commit_;
 
+  // The navigation start in TimeTicks, not the wall time reported by Blink.
+  const base::TimeTicks navigation_start_;
+
   // We record separate metrics for events that occur after a background,
   // because metrics like layout/paint are delayed artificially
   // when they occur in the background.
   base::TimeTicks background_time_;
   base::TimeTicks foreground_time_;
   bool started_in_foreground_;
 
   PageLoadTiming timing_;
   GURL url_;
 
@@ skipping 58 matching lines @@
 
   scoped_ptr<PageLoadMetricsEmbedderInterface> embedder_interface_;
   base::ObserverList<PageLoadMetricsObserver, true> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(MetricsWebContentsObserver);
 };
 
 }  // namespace page_load_metrics
 
 #endif  // COMPONENTS_PAGE_LOAD_METRICS_BROWSER_PAGE_LOAD_METRICS_WEB_CONTENTS_OBSERVER_H_