[WIP] Allow scroll events to permanently change the default gesture handler in RootView

ui/views/widget/root_view.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 UI_VIEWS_WIDGET_ROOT_VIEW_H_
 #define UI_VIEWS_WIDGET_ROOT_VIEW_H_
 
 #include <string>
 
 #include "base/memory/ref_counted.h"
@@ skipping 170 matching lines @@
   // true if mouse_pressed_handler_ has been explicitly set
   bool explicit_mouse_handler_;
 
   // Last position/flag of a mouse press/drag. Used if capture stops and we need
   // to synthesize a release.
   int last_mouse_event_flags_;
   int last_mouse_event_x_;
   int last_mouse_event_y_;
 
   // The view currently handling gesture events. When set, this handler receives
-  // all gesture events, except when there is an event handler for the specific
-  // gesture (e.g. scroll).
+  // all gesture events.
   View* gesture_handler_;
 
-  // The view currently handling scroll gesture events.
-  View* scroll_gesture_handler_;
-
   scoped_ptr<internal::PreEventDispatchHandler> pre_dispatch_handler_;
   scoped_ptr<internal::PostEventDispatchHandler> post_dispatch_handler_;
 
   // Focus ---------------------------------------------------------------------
 
   // The focus search algorithm.
   FocusSearch focus_search_;
 
   // Whether this root view belongs to the current active window.
   // bool activated_;
@@ skipping 13 matching lines @@
   // Tracks drag state for a view.
   View::DragInfo drag_info_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(RootView);
 };
 
 }  // namespace internal
 }  // namespace views
 
 #endif  // UI_VIEWS_WIDGET_ROOT_VIEW_H_