Revert of Implement a site engagement score based on time-on-site.

chrome/browser/engagement/site_engagement_helper.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_ENGAGEMENT_SITE_ENGAGEMENT_HELPER_H_
 #define CHROME_BROWSER_ENGAGEMENT_SITE_ENGAGEMENT_HELPER_H_
 
 #include "base/macros.h"
-#include "base/timer/timer.h"
-#include "content/public/browser/render_view_host.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "content/public/browser/web_contents_user_data.h"
 
 namespace content {
 class WebContents;
 }
 
 class GURL;
 
 // Per-WebContents class to handle updating the site engagement scores for
-// origins.
+// origins as the user navigates.
 class SiteEngagementHelper
     : public content::WebContentsObserver,
       public content::WebContentsUserData<SiteEngagementHelper> {
  public:
   ~SiteEngagementHelper() override;
 
-  static void SetSecondsBetweenUserInputCheck(double seconds);
-
  private:
-  // Class to encapsulate the user input listening.
-  //
-  // Time on site is recorded by detecting any user input (mouse or keypress)
-  // per some discrete time unit. If there is user input, then record a positive
-  // site engagement.
-  //
-  // When input is detected, SiteEngagementHelper::RecordUserInput is called,
-  // and the input detection callbacks are paused for
-  // g_seconds_between_user_input_check. This ensures that there is minimal
-  // overhead in input listening, and that input over an extended length of time
-  // is required to continually increase the engagement score.
-  class InputTracker {
-   public:
-    explicit InputTracker(SiteEngagementHelper* helper);
-    ~InputTracker();
-
-    // Callback to handle key press events from the RenderViewHost.
-    bool HandleKeyPressEvent(const content::NativeWebKeyboardEvent& event);
-
-    // Callback to handle mouse events from the RenderViewHost.
-    bool HandleMouseEvent(const blink::WebMouseEvent& event);
-
-    // Register callbacks to listen for user input.
-    void StartTracking(content::RenderViewHost* host);
-
-    // Pause listening for user input, restarting listening after
-    // g_seconds_between_user_input_check seconds.
-    void PauseTracking(content::RenderViewHost* host);
-
-    // Restart listening for user input.
-    void ResumeTracking();
-
-    // Stop listening for user input.
-    void StopTracking(content::RenderViewHost* host);
-
-    // Set the timer object for testing purposes.
-    void SetTimerForTesting(scoped_ptr<base::Timer> timer);
-
-    bool callbacks_added() { return callbacks_added_; }
-
-   private:
-    SiteEngagementHelper* helper_;
-    scoped_ptr<base::Timer> pause_timer_;
-    content::RenderWidgetHost::KeyPressEventCallback key_press_event_callback_;
-    content::RenderWidgetHost::MouseEventCallback mouse_event_callback_;
-    bool callbacks_added_;
-  };
-
   explicit SiteEngagementHelper(content::WebContents* web_contents);
   friend class content::WebContentsUserData<SiteEngagementHelper>;
-  friend class SiteEngagementServiceBrowserTest;
-  friend class TestSiteEngagementHelper;
-
-  // Ask the SiteEngagementService to record engagement via user input at the
-  // current contents location.
-  virtual void RecordUserInput();
-
-  virtual bool ShouldRecordEngagement();
 
   // content::WebContentsObserver overrides.
-  void DidNavigateMainFrame(
-      const content::LoadCommittedDetails& details,
-      const content::FrameNavigateParams& params) override;
-
-  void RenderViewHostChanged(content::RenderViewHost* old_host,
-                             content::RenderViewHost* new_host) override;
-
-  void WasShown() override;
-  void WasHidden() override;
-
-  InputTracker input_tracker_;
-  bool record_engagement_;
+  void DidStartNavigationToPendingEntry(
+      const GURL& url,
+      content::NavigationController::ReloadType reload_type) override;
 
   DISALLOW_COPY_AND_ASSIGN(SiteEngagementHelper);
 };
 
 #endif  // CHROME_BROWSER_ENGAGEMENT_SITE_ENGAGEMENT_HELPER_H_