WIP - compositor worker mega patch.

cc/trees/layer_tree_host_impl.h

Index: cc/trees/layer_tree_host_impl.h
diff --git a/cc/trees/layer_tree_host_impl.h b/cc/trees/layer_tree_host_impl.h
index 6d78c1663f361fb58ecf815f5c8845455aca63f7..00a1db087268079d378468de3451ef9bcf273fd8 100644
--- a/cc/trees/layer_tree_host_impl.h
+++ b/cc/trees/layer_tree_host_impl.h
@@ -16,6 +16,7 @@
 #include "base/memory/scoped_ptr.h"
 #include "base/time/time.h"
 #include "cc/animation/animation_registrar.h"
+#include "cc/animation/layer_tree_mutator.h"
 #include "cc/animation/scrollbar_animation_controller.h"
 #include "cc/base/cc_export.h"
 #include "cc/base/synced_property.h"
@@ -37,6 +38,7 @@
 #include "cc/scheduler/draw_result.h"
 #include "cc/scheduler/video_frame_controller.h"
 #include "cc/tiles/tile_manager.h"
+#include "cc/trees/layer_tree_host_common.h"
 #include "cc/trees/layer_tree_settings.h"
 #include "cc/trees/mutator_host_client.h"
 #include "cc/trees/task_runner_provider.h"
@@ -144,6 +146,7 @@ class CC_EXPORT LayerTreeHostImpl
       public TopControlsManagerClient,
       public ScrollbarAnimationControllerClient,
       public VideoFrameControllerClient,
+      public LayerTreeMutatorClient,
       public MutatorHostClient,
       public base::SupportsWeakPtr<LayerTreeHostImpl> {
  public:
@@ -231,6 +234,7 @@ class CC_EXPORT LayerTreeHostImpl
   virtual void BeginCommit();
   virtual void CommitComplete();
   virtual void UpdateAnimationState(bool start_ready_animations);
+  bool Mutate(base::TimeTicks monotinic_time);
   void ActivateAnimations();
   void Animate();
   void AnimatePendingTreeAfterCommit();
@@ -362,6 +366,9 @@ class CC_EXPORT LayerTreeHostImpl
               const gfx::Rect& clip,
               bool resourceless_software_draw) override;
 
+  // LayerTreeMutatorClient.
+  void SetNeedsMutate() override;
+
   // Called from LayerTreeImpl.
   void OnCanDrawStateChangedForTree();
 
@@ -595,6 +602,9 @@ class CC_EXPORT LayerTreeHostImpl
       scoped_ptr<FrameTimingTracker::CompositeTimingSet> composite_events,
       scoped_ptr<FrameTimingTracker::MainFrameTimingSet> main_frame_events);
 
+  void SetLayerTreeMutator(LayerTreeMutator* mutator);
+  LayerTreeMutator* mutator() { return mutator_; }
+
   base::SingleThreadTaskRunner* GetTaskRunner() const {
     DCHECK(task_runner_provider_);
     return task_runner_provider_->HasImplThread()
@@ -822,10 +832,13 @@ class CC_EXPORT LayerTreeHostImpl
   SharedBitmapManager* shared_bitmap_manager_;
   gpu::GpuMemoryBufferManager* gpu_memory_buffer_manager_;
   TaskGraphRunner* task_graph_runner_;
+  LayerTreeMutator* mutator_;
   int id_;
 
   std::set<SwapPromiseMonitor*> swap_promise_monitor_;
 
+  bool is_scrolling_;
+
   bool requires_high_res_to_draw_;
   bool is_likely_to_require_a_draw_;