Let LayerTreeHostImpl::ScrollAnimated scroll the outer viewport.

cc/input/input_handler.h

 // Copyright 2011 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 CC_INPUT_INPUT_HANDLER_H_
 #define CC_INPUT_INPUT_HANDLER_H_
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/time/time.h"
@@ skipping 66 matching lines @@
   // Note these are used in a histogram. Do not reorder or delete existing
   // entries.
   enum ScrollStatus {
     SCROLL_ON_MAIN_THREAD = 0,
     SCROLL_STARTED,
     SCROLL_IGNORED,
     SCROLL_UNKNOWN,
     // This must be the last entry.
     ScrollStatusCount
   };
-  enum ScrollInputType { GESTURE, WHEEL, NON_BUBBLING_GESTURE };
+  enum ScrollInputType { GESTURE, WHEEL, ANIMATED_WHEEL, NON_BUBBLING_GESTURE };
 
   // Binds a client to this handler to receive notifications. Only one client
   // can be bound to an InputHandler. The client must live at least until the
   // handler calls WillShutdown() on the client.
   virtual void BindToClient(InputHandlerClient* client) = 0;
 
   // Selects a layer to be scrolled at a given point in viewport (logical
   // pixel) coordinates. Returns SCROLL_STARTED if the layer at the coordinates
   // can be scrolled, SCROLL_ON_MAIN_THREAD if the scroll event should instead
   // be delegated to the main thread, or SCROLL_IGNORED if there is nothing to
@@ skipping 47 matching lines @@
 
   virtual void PinchGestureBegin() = 0;
   virtual void PinchGestureUpdate(float magnify_delta,
                                   const gfx::Point& anchor) = 0;
   virtual void PinchGestureEnd() = 0;
 
   // Request another callback to InputHandlerClient::Animate().
   virtual void SetNeedsAnimateInput() = 0;
 
   // If there is a scroll active, this reports whether the scroll is on the
   // root layer, or on some other sublayer.

[tdresser, 2015/10/20 12:29:40]

Should we update this comment?

[skobes, 2015/10/20 18:28:15]

Done.

-  virtual bool IsCurrentlyScrollingRoot() const = 0;
+  virtual bool IsCurrentlyScrollingInnerViewport() const = 0;
 
   // Whether the layer under |viewport_point| is the currently scrolling layer.
   virtual bool IsCurrentlyScrollingLayerAt(const gfx::Point& viewport_point,
                                            ScrollInputType type) const = 0;
 
   virtual bool HaveWheelEventHandlersAt(const gfx::Point& viewport_point) = 0;
 
   // Whether the page should be given the opportunity to suppress scrolling by
   // consuming touch events that started at |viewport_point|.
   virtual bool DoTouchEventsBlockScrollAt(const gfx::Point& viewport_point) = 0;
@@ skipping 12 matching lines @@
   InputHandler() {}
   virtual ~InputHandler() {}
 
  private:
   DISALLOW_COPY_AND_ASSIGN(InputHandler);
 };
 
 }  // namespace cc
 
 #endif  // CC_INPUT_INPUT_HANDLER_H_