Route Scroll events through a cc::InputHandler

ui/views/controls/scrollbar/base_scroll_bar.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_CONTROLS_SCROLLBAR_BASE_SCROLL_BAR_H_
 #define UI_VIEWS_CONTROLS_SCROLLBAR_BASE_SCROLL_BAR_H_
 
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "ui/views/animation/scroll_animator.h"
@@ skipping 52 matching lines @@
 
   // Scroll the contents by the specified offset (contents coordinates).
   bool ScrollByContentsOffset(int contents_offset);
 
   // View overrides:
   bool OnMousePressed(const ui::MouseEvent& event) override;
   void OnMouseReleased(const ui::MouseEvent& event) override;
   void OnMouseCaptureLost() override;
   bool OnKeyPressed(const ui::KeyEvent& event) override;
   bool OnMouseWheel(const ui::MouseWheelEvent& event) override;
+  void OnScrollEvent(ui::ScrollEvent* event) override;
 
   // ui::EventHandler overrides:
   void OnGestureEvent(ui::GestureEvent* event) override;
 
   // ScrollBar overrides:
   void Update(int viewport_size,
               int content_size,
               int contents_scroll_offset) override;
   int GetLayoutSize() const override = 0;
   int GetPosition() const override;
@@ skipping 90 matching lines @@
   // TODO(tdresser): This should be removed when raw pixel scrolling for views
   // is enabled. See crbug.com/329354.
   gfx::Vector2dF roundoff_error_;
 
   DISALLOW_COPY_AND_ASSIGN(BaseScrollBar);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_CONTROLS_SCROLLBAR_BASE_SCROLL_BAR_H_