Add User Actions and adding more details to UMA metrics for overscroll navigation

content/browser/web_contents/aura/overscroll_window_delegate.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 CONTENT_BROWSER_WEB_CONTENTS_AURA_OVERSCROLL_WINDOW_DELEGATE_H_
 #define CONTENT_BROWSER_WEB_CONTENTS_AURA_OVERSCROLL_WINDOW_DELEGATE_H_
 
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "content/browser/renderer_host/overscroll_controller.h"
@@ skipping 11 matching lines @@
  public:
   OverscrollWindowDelegate(OverscrollControllerDelegate* delegate,
                            const gfx::Image& image);
 
  private:
   FRIEND_TEST_ALL_PREFIXES(OverscrollWindowDelegateTest, BasicOverscrollModes);
 
   ~OverscrollWindowDelegate() override;
 
   // Starts the overscroll gesture.
-  void StartOverscroll();
+  void StartOverscroll(OverscrollSource source);
 
   // Resets the overscroll state.
   void ResetOverscroll();
 
   // Completes or resets the overscroll from the current state.
   void CompleteOrResetOverscroll();
 
   // Updates the current horizontal overscroll.
-  void UpdateOverscroll(float delta_x);
+  void UpdateOverscroll(float delta_x, OverscrollSource source);
 
   // Overridden from ui::EventHandler.
   void OnKeyEvent(ui::KeyEvent* event) override;
   void OnMouseEvent(ui::MouseEvent* event) override;
   void OnScrollEvent(ui::ScrollEvent* event) override;
   void OnGestureEvent(ui::GestureEvent* event) override;
 
   // Delegate to which we forward overscroll events.
   OverscrollControllerDelegate* delegate_;
 
@@ skipping 14 matching lines @@
   // The threshold for starting the overscroll gesture for the current touch
   // input.
   float active_start_threshold_;
 
   DISALLOW_COPY_AND_ASSIGN(OverscrollWindowDelegate);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_WEB_CONTENTS_AURA_OVERSCROLL_WINDOW_DELEGATE_H_