Hook ScrollElasticityController to InputHandlerProxy

cc/trees/layer_tree_scroll_elasticity_client.h

+// Copyright 2014 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_TREES_LAYER_TREE_SCROLL_ELASTICITY_CLIENT_H_
+#define CC_TREES_LAYER_TREE_SCROLL_ELASTICITY_CLIENT_H_
+
+#include "cc/input/scroll_elasticity_controller.h"
+
+namespace cc {
+
+class LayerTreeHostImpl;
+
+// Interface between a LayerTreeHostImpl and a ScrollElasticityController. It
+// would be possible, in principle, for LayerTreeHostImpl to implement the
+// ScrollElasticityControllerClient interface itself. This artificial boundary
+// is introduced to reduce the amount of logic and state held directly inside
+// LayerTreeHostImpl.
+class CC_EXPORT LayerTreeScrollElasticityClient
+    : public ScrollElasticityControllerClient {
+ public:
+  explicit LayerTreeScrollElasticityClient(LayerTreeHostImpl* layer_tree);
+  virtual ~LayerTreeScrollElasticityClient();
+
+  // Interface between LayerTreeHostImpl and the controller.
+  void Animate(base::TimeTicks monotonic_time);
+
+ private:
+  // ScrollElasticityControllerClient implementation:
+  void BindToController(ScrollElasticityController* controller) override;
+  bool AllowsHorizontalStretching() override;
+  bool AllowsVerticalStretching() override;
+  gfx::Vector2dF StretchAmount() override;
+  bool PinnedInDirection(const gfx::Vector2dF& direction) override;
+  bool CanScrollHorizontally() override;
+  bool CanScrollVertically() override;
+  gfx::Vector2dF AbsoluteScrollPosition() override;
+  void ImmediateScrollBy(const gfx::Vector2dF& scroll) override;
+  void ImmediateScrollByWithoutContentEdgeConstraints(
+      const gfx::Vector2dF& scroll) override;
+  void StartSnapRubberbandTimer() override;
+  void StopSnapRubberbandTimer() override;
+  void AdjustScrollPositionToBoundsIfNecessary() override;
+
+  LayerTreeHostImpl* layer_tree_;
+  ScrollElasticityController* controller_;
+  gfx::Vector2dF stretch_offset_;
+  bool timer_active_;
+};
+
+}  // namespace cc
+
+#endif  // CC_TREES_LAYER_TREE_SCROLL_ELASTICITY_CLIENT_H_