Abandon startup profiling for first WebContents when it gets hidden or navigated to a different ...

chrome/browser/metrics/first_web_contents_profiler.h

 // Copyright 2014 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_METRICS_FIRST_WEB_CONTENTS_PROFILER_H_
 #define CHROME_BROWSER_METRICS_FIRST_WEB_CONTENTS_PROFILER_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "base/metrics/histogram.h"
 #include "content/public/browser/web_contents_observer.h"
@@ skipping 16 matching lines @@
     virtual void ProfilerFinishedCollectingMetrics() = 0;
   };
 
   // Creates a profiler for the active web contents. If there are multiple
   // browsers, the first one is chosen. If there are no browsers, returns
   // nullptr.
   static scoped_ptr<FirstWebContentsProfiler> CreateProfilerForFirstWebContents(
       Delegate* delegate);
 
  private:
+  // Reasons for which profiling is deemed complete. Logged in UMA (do not re-
+  // order or re-assign).
+  enum FinishReason {
+    // All metrics were successfully gathered.
+    DONE = 0,
+    // Abandon if blocking UI was shown during startup.
+    ABANDON_BLOCKING_UI = 1,
+    // Abandon if the content is hidden (lowers scheduling priority).
+    ABANDON_CONTENT_HIDDEN = 2,
+    // Abandon if the content is destroyed.
+    ABANDON_CONTENT_DESTROYED = 3,
+    // Abandon if the WebContents navigates away from its initial page.
+    ABANDON_NAVIGATION = 4,
+    // Must stay last.
+    COUNT

[rkaplow, 2015/10/20 20:08:30]

usually I see this as something like ENUM_MAX which is a bit more obvious but
not a big deal

[gab, 2015/10/20 20:16:21]

Done.

+  };
+
   FirstWebContentsProfiler(content::WebContents* web_contents,
                            Delegate* delegate);
 
   // content::WebContentsObserver:
   void DidFirstVisuallyNonEmptyPaint() override;
   void DocumentOnLoadCompletedInMainFrame() 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.
   bool IsFinishedCollectingMetrics();
 
   // Informs the delegate that this instance has finished collecting all of its
-  // metrics.
-  void FinishedCollectingMetrics();
+  // metrics. Logs |finish_reason| to UMA.
+  void FinishedCollectingMetrics(FinishReason finish_reason);
 
   // Initialize histograms for unresponsiveness metrics.
   void InitHistograms();
 
+  // Becomes true on the first invocation of NavigationEntryCommitted() for the
+  // main frame. Any follow-up navigation to a different page will result in
+  // aborting first WebContents profiling.
+  bool initial_entry_committed_;
+
   // Whether an attempt was made to collect the "NonEmptyPaint" metric.
   bool collected_paint_metric_;
 
   // Whether an attempt was made to collect the "MainFrameLoad" metric.
   bool collected_load_metric_;
 
   // |delegate_| owns |this|.
   Delegate* delegate_;
 
   // Histogram that keeps track of response times for the watched thread.
@@ skipping 11 matching lines @@
   // Histogram that keeps track of response times for the watched thread.
   base::HistogramBase* unresponsiveness_1sec_histogram_;
 
   // Histogram that keeps track of response times for the watched thread.
   base::HistogramBase* unresponsiveness_10sec_histogram_;
 
   DISALLOW_COPY_AND_ASSIGN(FirstWebContentsProfiler);
 };
 
 #endif  // CHROME_BROWSER_METRICS_FIRST_WEB_CONTENTS_PROFILER_H_