Add start/finish navigation to startup metrics.

chrome/browser/metrics/first_web_contents_profiler.h

Index: chrome/browser/metrics/first_web_contents_profiler.h
diff --git a/chrome/browser/metrics/first_web_contents_profiler.h b/chrome/browser/metrics/first_web_contents_profiler.h
index 376e4f6f9cbe40c48a2211897facff95e442caaa..96e58bd1aa6b019d2ccd402090ac2e7ac8096c48 100644
--- a/chrome/browser/metrics/first_web_contents_profiler.h
+++ b/chrome/browser/metrics/first_web_contents_profiler.h
@@ -37,7 +37,9 @@ class FirstWebContentsProfiler : public content::WebContentsObserver {
     // Abandon if the content is destroyed.
     ABANDON_CONTENT_DESTROYED = 3,
     // Abandon if the WebContents navigates away from its initial page.
-    ABANDON_NAVIGATION = 4,
+    ABANDON_NEW_NAVIGATION = 4,
+    // Abandon if the WebContents fails to load (e.g. network error, etc.).
+    ABANDON_NAVIGATION_ERROR = 5,
     ENUM_MAX
   };
 
@@ -47,12 +49,18 @@ class FirstWebContentsProfiler : public content::WebContentsObserver {
   // content::WebContentsObserver:
   void DidFirstVisuallyNonEmptyPaint() override;
   void DocumentOnLoadCompletedInMainFrame() override;
+  void DidStartNavigation(
+      content::NavigationHandle* navigation_handle) override;
+  void DidFinishNavigation(
+      content::NavigationHandle* navigation_handle) override;
   void NavigationEntryCommitted(
       const content::LoadCommittedDetails& load_details) override;
   void WasHidden() override;
   void WebContentsDestroyed() override;
 
-  // Whether this instance has finished collecting all of its metrics.
+  // Whether this instance has finished collecting first-paint and main-frame-
+  // load metrics (navigation metrics are recorded on a best effort but don't
+  // prevent the FirstWebContentsProfiler from calling it).
   bool IsFinishedCollectingMetrics();
 
   // Logs |finish_reason| to UMA and deletes this FirstWebContentsProfiler.
@@ -72,6 +80,12 @@ class FirstWebContentsProfiler : public content::WebContentsObserver {
   // Whether an attempt was made to collect the "MainFrameLoad" metric.
   bool collected_load_metric_;
 
+  // Whether an attempt was made to collect the "MainNavigationStart" metric.
+  bool collected_main_navigation_start_metric_;
+
+  // Whether an attempt was made to collect the "MainNavigationFinished" metric.
+  bool collected_main_navigation_finished_metric_;
+
   // Histogram that keeps track of response times for the watched thread.
   base::HistogramBase* responsiveness_histogram_;