Update from https://crrev.com/314320

cc/layers/layer_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_LAYERS_LAYER_IMPL_H_
 #define CC_LAYERS_LAYER_IMPL_H_
 
 #include <set>
 #include <string>
 #include <vector>
 
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/values.h"
 #include "cc/animation/animation_delegate.h"
 #include "cc/animation/layer_animation_controller.h"
 #include "cc/animation/layer_animation_value_observer.h"
 #include "cc/animation/layer_animation_value_provider.h"
 #include "cc/base/cc_export.h"
 #include "cc/base/region.h"
 #include "cc/base/scoped_ptr_vector.h"
+#include "cc/base/synced_property.h"
 #include "cc/debug/frame_timing_request.h"
 #include "cc/input/input_handler.h"
 #include "cc/input/scrollbar.h"
 #include "cc/layers/draw_properties.h"
 #include "cc/layers/layer_lists.h"
 #include "cc/layers/layer_position_constraint.h"
 #include "cc/layers/render_surface_impl.h"
 #include "cc/output/filter_operations.h"
 #include "cc/quads/shared_quad_state.h"
 #include "cc/resources/resource_provider.h"
@@ skipping 42 matching lines @@
 };
 
 class CC_EXPORT LayerImpl : public LayerAnimationValueObserver,
                             public LayerAnimationValueProvider,
                             public AnimationDelegate {
  public:
   // Allows for the ownership of the total scroll offset to be delegated outside
   // of the layer.
   class ScrollOffsetDelegate {
    public:
-    virtual void SetTotalScrollOffset(const gfx::ScrollOffset& new_value) = 0;
-    virtual gfx::ScrollOffset GetTotalScrollOffset() = 0;
+    virtual void SetCurrentScrollOffset(const gfx::ScrollOffset& new_value) = 0;
+    virtual gfx::ScrollOffset GetCurrentScrollOffset() = 0;
     virtual bool IsExternalFlingActive() const = 0;
     virtual void Update() const = 0;
   };
 
+  typedef SyncedProperty<AdditionGroup<gfx::ScrollOffset>> SyncedScrollOffset;
   typedef LayerImplList RenderSurfaceListType;
   typedef LayerImplList LayerListType;
   typedef RenderSurfaceImpl RenderSurfaceType;
 
   enum RenderingContextConstants { NO_RENDERING_CONTEXT = 0 };
 
+  static scoped_ptr<LayerImpl> Create(
+      LayerTreeImpl* tree_impl,
+      int id,
+      scoped_refptr<SyncedScrollOffset> scroll_offset) {
+    return make_scoped_ptr(new LayerImpl(tree_impl, id, scroll_offset));
+  }
+
   static scoped_ptr<LayerImpl> Create(LayerTreeImpl* tree_impl, int id) {
     return make_scoped_ptr(new LayerImpl(tree_impl, id));
   }
 
   ~LayerImpl() override;
 
   int id() const { return layer_id_; }
 
   // LayerAnimationValueProvider implementation.
   gfx::ScrollOffset ScrollOffsetForAnimation() const override;
@@ skipping 272 matching lines @@
   gfx::Vector2dF bounds_delta() const { return bounds_delta_; }
 
   void SetContentBounds(const gfx::Size& content_bounds);
   gfx::Size content_bounds() const { return draw_properties_.content_bounds; }
 
   float contents_scale_x() const { return draw_properties_.contents_scale_x; }
   float contents_scale_y() const { return draw_properties_.contents_scale_y; }
   void SetContentsScale(float contents_scale_x, float contents_scale_y);
 
   void SetScrollOffsetDelegate(ScrollOffsetDelegate* scroll_offset_delegate);
-  void DidScroll();
+  void RefreshFromScrollDelegate();
   bool IsExternalFlingActive() const;
 
-  void SetScrollOffset(const gfx::ScrollOffset& scroll_offset);
-  void SetScrollOffsetAndDelta(const gfx::ScrollOffset& scroll_offset,
-                               const gfx::Vector2dF& scroll_delta);
-  gfx::ScrollOffset scroll_offset() const { return scroll_offset_; }
+  void SetCurrentScrollOffset(const gfx::ScrollOffset& scroll_offset);
+  void PushScrollOffsetFromMainThread(const gfx::ScrollOffset& scroll_offset);
+  gfx::ScrollOffset PullDeltaForMainThread();
+  gfx::ScrollOffset CurrentScrollOffset() const;
+  gfx::ScrollOffset BaseScrollOffset() const;
+  gfx::Vector2dF ScrollDelta() const;
+  void SetScrollDelta(const gfx::Vector2dF& delta);
 
   gfx::ScrollOffset MaxScrollOffset() const;
+  gfx::ScrollOffset ClampScrollOffsetToLimits(gfx::ScrollOffset offset) const;
   gfx::Vector2dF ClampScrollToMaxScrollOffset();
   void SetScrollbarPosition(ScrollbarLayerImplBase* scrollbar_layer,
                             LayerImpl* scrollbar_clip_layer,
                             bool on_resize) const;
-  void SetScrollDelta(const gfx::Vector2dF& scroll_delta);
-  gfx::Vector2dF ScrollDelta() const;
-
-  gfx::ScrollOffset TotalScrollOffset() const;
-
-  void SetSentScrollDelta(const gfx::Vector2dF& sent_scroll_delta);
-  gfx::Vector2dF sent_scroll_delta() const { return sent_scroll_delta_; }
+  void SetScrollCompensationAdjustment(const gfx::Vector2dF& scroll_offset) {
+    scroll_compensation_adjustment_ = scroll_offset;
+  }
+  gfx::Vector2dF ScrollCompensationAdjustment() const {
+    return scroll_compensation_adjustment_;
+  }
 
   // Returns the delta of the scroll that was outside of the bounds of the
   // initial scroll
   gfx::Vector2dF ScrollBy(const gfx::Vector2dF& scroll);
 
   void SetScrollClipLayer(int scroll_clip_layer_id);
   LayerImpl* scroll_clip_layer() const { return scroll_clip_layer_; }
   bool scrollable() const { return !!scroll_clip_layer_; }
 
   void set_user_scrollable_horizontal(bool scrollable) {
     user_scrollable_horizontal_ = scrollable;
   }
   bool user_scrollable_horizontal() const {
     return user_scrollable_horizontal_;
   }
   void set_user_scrollable_vertical(bool scrollable) {
     user_scrollable_vertical_ = scrollable;
   }
   bool user_scrollable_vertical() const { return user_scrollable_vertical_; }
 
   bool user_scrollable(ScrollbarOrientation orientation) const;
 
   void ApplySentScrollDeltasFromAbortedCommit();
-  void ApplyScrollDeltasSinceBeginMainFrame();
 
   void SetShouldScrollOnMainThread(bool should_scroll_on_main_thread) {
     should_scroll_on_main_thread_ = should_scroll_on_main_thread;
   }
   bool should_scroll_on_main_thread() const {
     return should_scroll_on_main_thread_;
   }
 
   void SetHaveWheelEventHandlers(bool have_wheel_event_handlers) {
     have_wheel_event_handlers_ = have_wheel_event_handlers;
@@ skipping 125 matching lines @@
 
   void Set3dSortingContextId(int id);
   int sorting_context_id() { return sorting_context_id_; }
 
   void PassFrameTimingRequests(
       std::vector<FrameTimingRequest>* frame_timing_requests);
   const std::vector<FrameTimingRequest>& frame_timing_requests() const {
     return frame_timing_requests_;
   }
 
+  SyncedScrollOffset* synced_scroll_offset() { return scroll_offset_.get(); }
+
  protected:
+  LayerImpl(LayerTreeImpl* layer_impl,
+            int id,
+            scoped_refptr<SyncedScrollOffset> scroll_offset);
   LayerImpl(LayerTreeImpl* layer_impl, int id);
 
   // Get the color and size of the layer's debug border.
   virtual void GetDebugBorderProperties(SkColor* color, float* width) const;
 
   void AppendDebugBorderQuad(RenderPass* render_pass,
                              const gfx::Size& content_bounds,
                              const SharedQuadState* shared_quad_state,
                              AppendQuadsData* append_quads_data) const;
   void AppendDebugBorderQuad(RenderPass* render_pass,
                              const gfx::Size& content_bounds,
                              const SharedQuadState* shared_quad_state,
                              AppendQuadsData* append_quads_data,
                              SkColor color,
                              float width) const;
 
   void NoteLayerPropertyChanged();
   void NoteLayerPropertyChangedForSubtree();
 
   // Note carefully this does not affect the current layer.
   void NoteLayerPropertyChangedForDescendants();
 
  private:
+  void PushScrollOffset(const gfx::ScrollOffset* scroll_offset);
+  void DidUpdateScrollOffset();
   void NoteLayerPropertyChangedForDescendantsInternal();
 
   virtual const char* LayerTypeAsString() const;
 
   // Properties internal to LayerImpl
   LayerImpl* parent_;
   OwnedLayerImplList children_;
 
   LayerImpl* scroll_parent_;
 
   // Storing a pointer to a set rather than a set since this will be rarely
   // used. If this pointer turns out to be too heavy, we could have this (and
   // the scroll parent above) be stored in a LayerImpl -> scroll_info
   // map somewhere.
   scoped_ptr<std::set<LayerImpl*>> scroll_children_;
 
   LayerImpl* clip_parent_;
   scoped_ptr<std::set<LayerImpl*>> clip_children_;
 
   // mask_layer_ can be temporarily stolen during tree sync, we need this ID to
   // confirm newly assigned layer is still the previous one
   int mask_layer_id_;
   scoped_ptr<LayerImpl> mask_layer_;
   int replica_layer_id_;  // ditto
   scoped_ptr<LayerImpl> replica_layer_;
   int layer_id_;
   LayerTreeImpl* layer_tree_impl_;
 
+  // Properties dynamically changeable on active tree.
+  scoped_refptr<SyncedScrollOffset> scroll_offset_;
+  gfx::Vector2dF bounds_delta_;
+
   // Properties synchronized from the associated Layer.
   gfx::Point3F transform_origin_;
   gfx::Size bounds_;
-  gfx::Vector2dF bounds_delta_;
-  gfx::ScrollOffset scroll_offset_;
   ScrollOffsetDelegate* scroll_offset_delegate_;
   LayerImpl* scroll_clip_layer_;
   bool scrollable_ : 1;
   bool should_scroll_on_main_thread_ : 1;
   bool have_wheel_event_handlers_ : 1;
   bool have_scroll_event_handlers_ : 1;
   bool user_scrollable_horizontal_ : 1;
   bool user_scrollable_vertical_ : 1;
   bool stacking_order_changed_ : 1;
   // Whether the "back" of this layer should draw.
@@ skipping 20 matching lines @@
   Region touch_event_handler_region_;
   SkColor background_color_;
 
   float opacity_;
   SkXfermode::Mode blend_mode_;
   gfx::PointF position_;
   gfx::Transform transform_;
 
   LayerPositionConstraint position_constraint_;
 
-  gfx::Vector2dF scroll_delta_;
-  gfx::Vector2dF sent_scroll_delta_;
-  gfx::ScrollOffset last_scroll_offset_;
+  gfx::Vector2dF scroll_compensation_adjustment_;
 
   int num_descendants_that_draw_content_;
 
   // The global depth value of the center of the layer. This value is used
   // to sort layers from back to front.
   float draw_depth_;
 
   FilterOperations filters_;
   FilterOperations background_filters_;
 
@@ skipping 44 matching lines @@
 
   std::vector<FrameTimingRequest> frame_timing_requests_;
   bool frame_timing_requests_dirty_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_LAYER_IMPL_H_