Add .SingleTab and .MultiTabs suffix to Startup.FirstWebContents.MainNavigationStart histogram.

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 <memory>
+namespace metrics {
 
-#include "base/macros.h"
-#include "content/public/browser/web_contents_observer.h"
+// Measures startup performance of the first active web contents.
+void BeginFirstWebContentsProfiling();
 
-namespace content {
-class WebContents;
-}  // namespace content
-
-// Measures start up performance of the first active web contents.
-// This class is declared on all platforms, but only defined on non-Android
-// platforms. Android code should not call any non-trivial methods on this
-// class.
-class FirstWebContentsProfiler : public content::WebContentsObserver {
- public:
-  // Creates a profiler for the active web contents. If there are multiple
-  // browsers, the first one is chosen. The resulting FirstWebContentsProfiler
-  // owns itself.
-  static void Start();
-
- 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_NEW_NAVIGATION = 4,
-    // Abandon if the WebContents fails to load (e.g. network error, etc.).
-    ABANDON_NAVIGATION_ERROR = 5,
-    ENUM_MAX
-  };
-  explicit FirstWebContentsProfiler(content::WebContents* web_contents);
-  ~FirstWebContentsProfiler() override = default;
-
-  // content::WebContentsObserver:
-  void DidFirstVisuallyNonEmptyPaint() override;
-  void DocumentOnLoadCompletedInMainFrame() override;
-  void DidStartNavigation(
-      content::NavigationHandle* navigation_handle) override;
-  void DidFinishNavigation(
-      content::NavigationHandle* navigation_handle) override;
-  void WasHidden() override;
-  void WebContentsDestroyed() override;
-
-  // 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.
-  void FinishedCollectingMetrics(FinishReason finish_reason);
-
-  // 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_;
-
-  // 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_;
-
-  DISALLOW_COPY_AND_ASSIGN(FirstWebContentsProfiler);
-};
+}  // namespace metrics
 
 #endif  // CHROME_BROWSER_METRICS_FIRST_WEB_CONTENTS_PROFILER_H_