Propogate the tab foreground, background change events to data use

chrome/browser/data_use_measurement/data_use_web_contents_observer.h

 // Copyright 2016 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_DATA_USE_MEASUREMENT_DATA_USE_WEB_CONTENTS_OBSERVER_H_
 #define CHROME_BROWSER_DATA_USE_MEASUREMENT_DATA_USE_WEB_CONTENTS_OBSERVER_H_
 
 #include "base/macros.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "content/public/browser/web_contents_user_data.h"
@@ skipping 22 matching lines @@
   ~DataUseWebContentsObserver() override;
 
   // WebContentsObserver implementation:
   void RenderFrameCreated(content::RenderFrameHost* render_frame_host) override;
   void RenderFrameDeleted(content::RenderFrameHost* render_frame_host) override;
   void DidStartNavigation(
       content::NavigationHandle* navigation_handle) override;
   void ReadyToCommitNavigation(
       content::NavigationHandle* navigation_handle) override;
 
+  // Called every time the WebContents changes visibility.

[RyanSturm, 2016/12/13 22:04:20]

Can you remove this comment and delete the whitespace between the methods from
WebContentsObserver implementation.

[Raj, 2016/12/14 23:00:50]

Done.

+  void WasShown();
+  void WasHidden();
+
+  void RenderFrameHostChanged(content::RenderFrameHost* old_host,
+                              content::RenderFrameHost* new_host);
+
  private:
   friend class content::WebContentsUserData<DataUseWebContentsObserver>;
   DataUseWebContentsObserver(content::WebContents* web_contents,
                              ChromeDataUseAscriberService* service);
   ChromeDataUseAscriberService* const service_;
 
   DISALLOW_COPY_AND_ASSIGN(DataUseWebContentsObserver);
 };
 
 }  // namespace data_use_measurement
 
 #endif  // CHROME_BROWSER_DATA_USE_MEASUREMENT_DATA_USE_WEB_CONTENTS_OBSERVER_H_