Enable the Sky compositor again

sky/compositor/layer_host.h

 // Copyright 2014 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 SKY_COMPOSITOR_LAYER_HOST_H_
 #define SKY_COMPOSITOR_LAYER_HOST_H_
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "mojo/skia/ganesh_context.h"
@@ skipping 23 matching lines @@
   }
 
   ResourceManager* resource_manager() const {
     return const_cast<ResourceManager*>(&resource_manager_);
   }
 
   void SetNeedsAnimate();
   void SetRootLayer(scoped_refptr<Layer> layer);
 
  private:
+  enum State {
+    kIdle,
+    kWaitingForBeginFrame,
+    kProducingFrame,
+    kWaitingForSurfaceToUploadFrame,
+  };
+
   // SurfaceHolder::Client
   void OnSurfaceIdAvailable(mojo::SurfaceIdPtr surface_id) override;
   void ReturnResources(
       mojo::Array<mojo::ReturnedResourcePtr> resources) override;
 
   // Scheduler::Client
   void BeginFrame(base::TimeTicks frame_time,
                   base::TimeTicks deadline) override;
 
   void Upload(Layer* layer);
 
   LayerHostClient* client_;
+  State state_;
   SurfaceHolder surface_holder_;
   base::WeakPtr<mojo::GLContext> gl_context_;
   mojo::GaneshContext ganesh_context_;
   ResourceManager resource_manager_;
   Scheduler scheduler_;
 
   scoped_refptr<Layer> root_layer_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerHost);
 };
 
 }  // namespace sky
 
 #endif  // SKY_COMPOSITOR_LAYER_HOST_H_