WIP - compositor worker mega patch.

cc/trees/threaded_channel.cc

Index: cc/trees/threaded_channel.cc
diff --git a/cc/trees/threaded_channel.cc b/cc/trees/threaded_channel.cc
index 3d2eb33aeea4c201910de76db2c7f3ede10cd035..3b6a12f2e21d624083e1f44dab8a3e333a4b7241 100644
--- a/cc/trees/threaded_channel.cc
+++ b/cc/trees/threaded_channel.cc
@@ -7,6 +7,7 @@
 #include "base/bind.h"
 #include "base/single_thread_task_runner.h"
 #include "base/trace_event/trace_event.h"
+#include "cc/animation/layer_tree_mutator.h"
 #include "cc/trees/layer_tree_host.h"
 
 namespace cc {
@@ -52,6 +53,12 @@ void ThreadedChannel::InitializeOutputSurfaceOnImpl(
                             proxy_impl_weak_ptr_, output_surface));
 }
 
+void ThreadedChannel::InitializeMutatorOnImpl(LayerTreeMutator* mutator) {
+  ImplThreadTaskRunner()->PostTask(
+      FROM_HERE, base::Bind(&ProxyImpl::InitializeMutatorOnImpl,
+                            proxy_impl_weak_ptr_, mutator));
+}
+
 void ThreadedChannel::MainThreadHasStoppedFlingingOnImpl() {
   DCHECK(IsMainThread());
   ImplThreadTaskRunner()->PostTask(