compositor-worker: cc->blink mutation plumbing

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 a7d6b083235eca111337803d8af04cf9f367e3e1..901c8abe1d336b012e8cc4b02c2b0ce3f545709b 100644
--- a/cc/trees/layer_tree_host_impl.h
+++ b/cc/trees/layer_tree_host_impl.h
@@ -12,9 +12,12 @@
 #include <unordered_map>
 #include <vector>
 
+#include "base/callback.h"
 #include "base/macros.h"
 #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/base/cc_export.h"
 #include "cc/base/synced_property.h"
 #include "cc/debug/frame_timing_tracker.h"
@@ -79,6 +82,8 @@ class UIResourceRequest;
 struct ScrollAndScaleSet;
 class Viewport;
 
+using BeginFrameCallbackList = std::vector<base::Closure>;
+
 enum class GpuRasterizationStatus {
   ON,
   ON_FORCED,
@@ -461,6 +466,8 @@ class CC_EXPORT LayerTreeHostImpl
 
   const gfx::Transform& DrawTransform() const;
 
+  scoped_ptr<BeginFrameCallbackList> ProcessLayerTreeMutations();
+
   scoped_ptr<ScrollAndScaleSet> ProcessScrollDeltas();
 
   void set_max_memory_needed_bytes(size_t bytes) {
@@ -616,6 +623,9 @@ class CC_EXPORT LayerTreeHostImpl
                                        const ScrollTree& scroll_tree,
                                        ScrollNode* scroll_node) const;
 
+  void SetLayerTreeMutator(LayerTreeMutator* mutator);
+  LayerTreeMutator* mutator() { return mutator_; }
+
  protected:
   LayerTreeHostImpl(
       const LayerTreeSettings& settings,
@@ -849,6 +859,8 @@ class CC_EXPORT LayerTreeHostImpl
 
   scoped_ptr<Viewport> viewport_;
 
+  LayerTreeMutator* mutator_;
+
   DISALLOW_COPY_AND_ASSIGN(LayerTreeHostImpl);
 };