Connect LTHI::ScrollAnimated to cc::Viewport

cc/layers/viewport.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 CC_LAYERS_VIEWPORT_H_
 #define CC_LAYERS_VIEWPORT_H_
 
+#include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "cc/layers/layer_impl.h"
 #include "ui/gfx/geometry/vector2d_f.h"
 
 namespace cc {
 
 class LayerTreeHostImpl;
 
 // Encapsulates gesture handling logic on the viewport layers. The "viewport"
@@ skipping 21 matching lines @@
   // affecting the top controls or outer viewport.
   void Pan(const gfx::Vector2dF& delta);
 
   // Scrolls the viewport, applying the unique bubbling between the inner and
   // outer viewport. Scrolls can be consumed by top controls.
   ScrollResult ScrollBy(const gfx::Vector2dF& delta,
                         const gfx::Point& viewport_point,
                         bool is_wheel_scroll,
                         bool affect_top_controls);
 
+  // Scrolls the viewport, bubbling the delta between the inner and outer
+  // viewport. Only animates either of the two viewports.
+  gfx::Vector2dF ScrollAnimated(const gfx::Vector2dF& delta);
+
   void PinchUpdate(float magnify_delta, const gfx::Point& anchor);
   void PinchEnd();
 
  private:
   explicit Viewport(LayerTreeHostImpl* host_impl);
 
+  // Returns true if viewport_delta is stricly less than pendinf_delta.

[bokan, 2016/04/06 13:35:52]

Nit: s/pendinf_delta/pending_delta

[ymalik, 2016/04/06 15:33:45]

Done.

+  static bool ShouldAnimateViewport(const gfx::Vector2dF& viewport_delta,
+                                    const gfx::Vector2dF& pending_delta);
   bool ShouldTopControlsConsumeScroll(const gfx::Vector2dF& scroll_delta) const;
   gfx::Vector2dF AdjustOverscroll(const gfx::Vector2dF& delta) const;
 
   // Sends the delta to the top controls, returns the amount applied.
   gfx::Vector2dF ScrollTopControls(const gfx::Vector2dF& delta);
 
   gfx::ScrollOffset MaxTotalScrollOffset() const;
   gfx::ScrollOffset TotalScrollOffset() const;
 
   LayerImpl* InnerScrollLayer() const;
   LayerImpl* OuterScrollLayer() const;
 
   void SnapPinchAnchorIfWithinMargin(const gfx::Point& anchor);
 
   LayerTreeHostImpl* host_impl_;
 
   bool pinch_zoom_active_;
 
   // The pinch zoom anchor point is adjusted by this amount during a pinch. This
   // is used to "snap" a pinch-zoom to the edge of the screen.
   gfx::Vector2d pinch_anchor_adjustment_;
 
+  FRIEND_TEST_ALL_PREFIXES(ViewportTest, ShouldAnimateViewport);
+
   DISALLOW_COPY_AND_ASSIGN(Viewport);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_VIEWPORT_H_