Communicate MT changes to impl-only scroll offset animations

cc/animation/animation_host.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_ANIMATION_ANIMATION_HOST_H_
 #define CC_ANIMATION_ANIMATION_HOST_H_
 
 #include <memory>
 #include <unordered_map>
 
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/memory/ref_counted.h"
 #include "base/time/time.h"
 #include "cc/animation/animation.h"
-#include "cc/animation/scroll_offset_animations_impl.h"
 #include "cc/base/cc_export.h"
 #include "cc/trees/mutator_host_client.h"
 #include "ui/gfx/geometry/box_f.h"
 #include "ui/gfx/geometry/vector2d_f.h"
 
 namespace gfx {
 class ScrollOffset;
 }
 
 namespace cc {
 
 class AnimationEvents;
 class AnimationPlayer;
 class AnimationTimeline;
 class ElementAnimations;
 class LayerTreeHost;
+class ScrollOffsetAnimations;
+class ScrollOffsetAnimationsImpl;
 
 enum class ThreadInstance { MAIN, IMPL };
 
 // An AnimationHost contains all the state required to play animations.
 // Specifically, it owns all the AnimationTimelines objects.
 // There is just one AnimationHost for LayerTreeHost on main renderer thread
 // and just one AnimationHost for LayerTreeHostImpl on impl thread.
 // We synchronize them during the commit process in a one-way data flow process
 // (PushPropertiesTo).
 // An AnimationHost talks to its correspondent LayerTreeHost via
@@ skipping 99 matching lines @@
                                      const gfx::ScrollOffset& target_offset,
                                      const gfx::ScrollOffset& current_offset);
   bool ImplOnlyScrollAnimationUpdateTarget(
       ElementId element_id,
       const gfx::Vector2dF& scroll_delta,
       const gfx::ScrollOffset& max_scroll_offset,
       base::TimeTicks frame_monotonic_time);
 
   void ScrollAnimationAbort(bool needs_completion);
 
+  // This should only be called from the main thread.
+  ScrollOffsetAnimations& scroll_offset_animations() const;
+
   // Registers the given element animations as active. An active element
   // animations is one that has a running animation that needs to be ticked.
   void DidActivateElementAnimations(ElementAnimations* element_animations);
 
   // Unregisters the given element animations. When this happens, the
   // element animations will no longer be ticked (since it's not active).
   void DidDeactivateElementAnimations(ElementAnimations* element_animations);
 
   // Registers the given ElementAnimations as alive.
   void RegisterElementAnimations(ElementAnimations* element_animations);
@@ skipping 20 matching lines @@
   ElementToAnimationsMap element_to_animations_map_;
   ElementToAnimationsMap active_element_to_animations_map_;
 
   // A list of all timelines which this host owns.
   using IdToTimelineMap =
       std::unordered_map<int, scoped_refptr<AnimationTimeline>>;
   IdToTimelineMap id_to_timeline_map_;
 
   MutatorHostClient* mutator_host_client_;
 
+  std::unique_ptr<ScrollOffsetAnimations> scroll_offset_animations_;
   std::unique_ptr<ScrollOffsetAnimationsImpl> scroll_offset_animations_impl_;
 
   const ThreadInstance thread_instance_;
 
   bool supports_scroll_animations_;
   bool animation_waiting_for_deletion_;
 
   DISALLOW_COPY_AND_ASSIGN(AnimationHost);
 };
 
 }  // namespace cc
 
 #endif  // CC_ANIMATION_ANIMATION_HOST_H_