[page_load_metrics] Add a NavigationThrottle for richer abort metrics

chrome/browser/page_load_metrics/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 CHROME_BROWSER_PAGE_LOAD_METRICS_METRICS_WEB_CONTENTS_OBSERVER_H_
 #define CHROME_BROWSER_PAGE_LOAD_METRICS_METRICS_WEB_CONTENTS_OBSERVER_H_
 
 #include <map>
 #include <memory>
 #include <vector>
@@ skipping 172 matching lines @@
                    bool is_certainly_browser_timestamp);
   void UpdateAbort(UserAbortType abort_type,
                    base::TimeTicks timestamp,
                    bool is_certainly_browser_timestamp);
 
   // This method returns true if this page load has been aborted with type of
   // ABORT_OTHER, and the |abort_cause_time| is within a sufficiently close
   // delta to when it was aborted. Note that only provisional loads can be
   // aborted with ABORT_OTHER. While this heuristic is coarse, it works better
   // and is simpler than other feasible methods. See https://goo.gl/WKRG98.
-  bool IsLikelyProvisionalAbort(base::TimeTicks abort_cause_time);
+  bool IsLikelyProvisionalAbort(base::TimeTicks abort_cause_time) const;
 
   bool MatchesOriginalNavigation(content::NavigationHandle* navigation_handle);
 
   // Only valid to call post-commit.
   const GURL& committed_url() const {
     DCHECK(!commit_time_.is_null());
     return url_;
   }
 
   base::TimeTicks navigation_start() const { return navigation_start_; }
 
   PageLoadExtraInfo ComputePageLoadExtraInfo();
 
+  ui::PageTransition page_transition() const { return page_transition_; }
+
  private:
   // This function converts a TimeTicks value taken in the browser process
   // to navigation_start_ if:
   // - base::TimeTicks is not comparable across processes because the clock
   // is not system wide monotonic.
   // - *event_time < navigation_start_
   void ClampBrowserTimestampIfInterProcessTimeTickSkew(
       base::TimeTicks* event_time);
 
   void UpdateAbortInternal(UserAbortType abort_type,
@@ skipping 35 matching lines @@
   // 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_;
   PageLoadMetadata metadata_;
 
+  ui::PageTransition page_transition_;
+
   // This is a subtle member. If a provisional load A gets aborted by
   // provisional load B, which gets aborted by C that eventually commits, then
   // there exists an abort chain of length 2, starting at A's navigation_start.
   // This is useful because it allows histograming abort chain lengths based on
   // what the last load's transition type is. i.e. holding down F-5 to spam
   // reload will produce a long chain with the RELOAD transition.
   const int aborted_chain_size_;
 
   // This member counts consecutive provisional aborts that share a url. It will
   // always be less than or equal to |aborted_chain_size_|.
@@ skipping 20 matching lines @@
       content::WebContents* web_contents,
       std::unique_ptr<PageLoadMetricsEmbedderInterface> embedder_interface);
   MetricsWebContentsObserver(
       content::WebContents* web_contents,
       std::unique_ptr<PageLoadMetricsEmbedderInterface> embedder_interface);
   ~MetricsWebContentsObserver() override;
 
   // content::WebContentsObserver implementation:
   bool OnMessageReceived(const IPC::Message& message,
                          content::RenderFrameHost* render_frame_host) override;
-  void DidStartNavigation(
-      content::NavigationHandle* navigation_handle) override;
   void DidFinishNavigation(
       content::NavigationHandle* navigation_handle) override;
   void DidRedirectNavigation(
       content::NavigationHandle* navigation_handle) override;
   void NavigationStopped() override;
   void OnInputEvent(const blink::WebInputEvent& event) override;
   void WasShown() override;
   void WasHidden() override;
   void RenderProcessGone(base::TerminationStatus status) override;
   void RenderViewHostChanged(content::RenderViewHost* old_host,
                              content::RenderViewHost* new_host) override;
 
+  // This method is forwarded from the MetricsNavigationThrottle.
+  void WillStartNavigationRequest(content::NavigationHandle* navigation_handle);
+
   // Flush any buffered metrics, as part of the metrics subsystem persisting
   // metrics as the application goes into the background. The application may be
   // killed at any time after this method is invoked without further
   // notification.
   void FlushMetricsOnAppEnterBackground();
 
   // This getter function is required for testing.
   const PageLoadExtraInfo GetPageLoadExtraInfoForCommittedLoad();
 
  private:
@@ skipping 57 matching lines @@
 
   // Has the MWCO observed at least one navigation?
   bool has_navigated_;
 
   DISALLOW_COPY_AND_ASSIGN(MetricsWebContentsObserver);
 };
 
 }  // namespace page_load_metrics
 
 #endif  // CHROME_BROWSER_PAGE_LOAD_METRICS_METRICS_WEB_CONTENTS_OBSERVER_H_