Move viewport scrolling logic into separate class

cc/trees/layer_tree_host_impl.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_TREES_LAYER_TREE_HOST_IMPL_H_
 #define CC_TREES_LAYER_TREE_HOST_IMPL_H_
 
 #include <set>
 #include <string>
 #include <vector>
@@ skipping 55 matching lines @@
 class ResourcePool;
 class ScrollElasticityHelper;
 class ScrollbarLayerImplBase;
 class SwapPromise;
 class SwapPromiseMonitor;
 class TextureMailboxDeleter;
 class TopControlsManager;
 class UIResourceBitmap;
 class UIResourceRequest;
 struct ScrollAndScaleSet;
+class Viewport;
 
 enum class GpuRasterizationStatus {
   ON,
   ON_FORCED,
   OFF_DEVICE,
   OFF_VIEWPORT,
   OFF_CONTENT
 };
 
 // LayerTreeHost->Proxy callback interface.
@@ skipping 431 matching lines @@
       scoped_ptr<TileTaskWorkerPool>* tile_task_worker_pool,
       scoped_ptr<ResourcePool>* resource_pool,
       scoped_ptr<ResourcePool>* staging_resource_pool);
 
   bool prepare_tiles_needed() const { return tile_priorities_dirty_; }
 
   FrameTimingTracker* frame_timing_tracker() {
     return frame_timing_tracker_.get();
   }
 
+  gfx::Vector2dF ScrollLayer(LayerImpl* layer_impl,
+                             const gfx::Vector2dF& delta,
+                             const gfx::Point& viewport_point,
+                             bool is_wheel_scroll);
+
  protected:
   LayerTreeHostImpl(
       const LayerTreeSettings& settings,
       LayerTreeHostImplClient* client,
       Proxy* proxy,
       RenderingStatsInstrumentation* rendering_stats_instrumentation,
       SharedBitmapManager* shared_bitmap_manager,
       gpu::GpuMemoryBufferManager* gpu_memory_buffer_manager,
       TaskGraphRunner* task_graph_runner,
       int id);
 
   // Virtual for testing.
   virtual void AnimateLayers(base::TimeTicks monotonic_time);
 
   bool is_likely_to_require_a_draw() const {
     return is_likely_to_require_a_draw_;
   }
 
   LayerTreeHostImplClient* client_;
   Proxy* proxy_;
 
  private:
+  gfx::Vector2dF ScrollLayerWithViewportSpaceDelta(
+      LayerImpl* layer_impl,
+      const gfx::PointF& viewport_point,
+      const gfx::Vector2dF& viewport_delta);
+
   void CreateAndSetRenderer();
   void CreateAndSetTileManager();
   void DestroyTileManager();
   void ReleaseTreeResources();
   void RecreateTreeResources();
   void EnforceZeroBudget(bool zero_budget);
 
   bool IsSynchronousSingleThreaded() const;
 
+  Viewport* viewport() { return viewport_.get(); }
+
   // Scroll by preferring to move the outer viewport first, only moving the
   // inner if the outer is at its scroll extents.
   void ScrollViewportBy(gfx::Vector2dF scroll_delta);
   // Scroll by preferring to move the inner viewport first, only moving the
   // outer if the inner is at its scroll extents.
   void ScrollViewportInnerFirst(gfx::Vector2dF scroll_delta);
   void AnimatePageScale(base::TimeTicks monotonic_time);
   void AnimateScrollbars(base::TimeTicks monotonic_time);
   void AnimateTopControls(base::TimeTicks monotonic_time);
 
-  bool ShouldTopControlsConsumeScroll(const gfx::Vector2dF& scroll_delta) const;
-
-  gfx::Vector2dF ScrollLayerWithViewportSpaceDelta(
-      LayerImpl* layer_impl,
-      float scale_from_viewport_to_screen_space,
-      const gfx::PointF& viewport_point,
-      const gfx::Vector2dF& viewport_delta);
-
   void TrackDamageForAllSurfaces(
       LayerImpl* root_draw_layer,
       const LayerImplList& render_surface_layer_list);
 
   void UpdateTileManagerMemoryPolicy(const ManagedMemoryPolicy& policy);
 
   // This function should only be called from PrepareToDraw, as DidDrawAllLayers
   // must be called if this helper function is called.  Returns DRAW_SUCCESS if
   // the frame should be drawn.
   DrawResult CalculateRenderPasses(FrameData* frame);
@@ skipping 154 matching lines @@
   int id_;
 
   std::set<SwapPromiseMonitor*> swap_promise_monitor_;
   std::vector<PictureLayerImpl::Pair> picture_layer_pairs_;
 
   bool requires_high_res_to_draw_;
   bool is_likely_to_require_a_draw_;
 
   scoped_ptr<FrameTimingTracker> frame_timing_tracker_;
 
+  scoped_ptr<Viewport> viewport_;
+
   DISALLOW_COPY_AND_ASSIGN(LayerTreeHostImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_LAYER_TREE_HOST_IMPL_H_