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

content/browser/renderer_host/overscroll_controller.h

 // Copyright (c) 2012 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_RENDERER_HOST_OVERSCROLL_CONTROLLER_H_
 #define CONTENT_BROWSER_RENDERER_HOST_OVERSCROLL_CONTROLLER_H_
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "third_party/WebKit/public/platform/WebGestureEvent.h"
 #include "third_party/WebKit/public/platform/WebInputEvent.h"
 
 namespace content {
 
 class RenderWidgetHostViewAuraOverscrollTest;
 class OverscrollControllerDelegate;
 
 // Indicates the direction that the scroll is heading in relative to the screen,
 // with the top being NORTH.
 enum OverscrollMode {
   OVERSCROLL_NONE,
   OVERSCROLL_NORTH,
   OVERSCROLL_SOUTH,
   OVERSCROLL_WEST,
   OVERSCROLL_EAST
 };
 
+// Indicates the source device that was used to trigger the overscroll gesture.
+enum OverscrollSource {

[mohsen, 2017/02/21 20:47:58]

I believe it's preferred to use "enum class". Then you can probably remove
OVERSCROLL prefix from values (just NONE, TOUCHPAD, TOUCHSCREEN).

[mfomitchev, 2017/02/23 02:59:42]

Done.

+  OVERSCROLL_SOURCE_NONE,
+  OVERSCROLL_TOUCHPAD,
+  OVERSCROLL_TOUCHSCREEN,
+};
+
 // When a page is scrolled beyond the scrollable region, it will trigger an
 // overscroll gesture. This controller receives the events that are dispatched
 // to the renderer, and the ACKs of events, and updates the overscroll gesture
 // status accordingly.
 class OverscrollController {
  public:
   OverscrollController();
   virtual ~OverscrollController();
 
   // This must be called when dispatching any event from the
@@ skipping 49 matching lines @@
 
   // Processes horizontal overscroll. This can update both the overscroll mode
   // and the over scroll amount (i.e. |overscroll_mode_|, |overscroll_delta_x_|
   // and |overscroll_delta_y_|). Returns true if overscroll was handled by the
   // delegate.
   bool ProcessOverscroll(float delta_x, float delta_y, bool is_touchpad);
 
   // Completes the desired action from the current gesture.
   void CompleteAction();
 
-  // Sets the overscroll mode (and triggers callback in the delegate when
-  // appropriate).
-  void SetOverscrollMode(OverscrollMode new_mode);
+  // Sets the overscroll mode and triggers callback in the delegate when
+  // appropriate. When a new overscroll is started (i.e. when |new_mode| is not
+  // equal to OVERSCROLL_NONE), |source| will be set to the device that
+  // triggered the overscroll gesture.
+  void SetOverscrollMode(OverscrollMode new_mode, OverscrollSource source);
 
   // Whether this event should be processed or not handled by the controller.
   bool ShouldProcessEvent(const blink::WebInputEvent& event);
 
   // The current state of overscroll gesture.
   OverscrollMode overscroll_mode_;
 
   // Used to keep track of the scrolling state.
   // If scrolling starts, and some scroll events are consumed at the beginning
   // of the scroll (i.e. some content on the web-page was scrolled), then do not
   // process any of the subsequent scroll events for generating overscroll
   // gestures.
   ScrollState scroll_state_;
 
   // The amount of overscroll in progress. These values are invalid when
   // |overscroll_mode_| is set to OVERSCROLL_NONE.
   float overscroll_delta_x_;
   float overscroll_delta_y_;
 
   // The delegate that receives the overscroll updates. The delegate is not
   // owned by this controller.
   OverscrollControllerDelegate* delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(OverscrollController);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_OVERSCROLL_CONTROLLER_H_