[WIP] cc: Plumb SurfaceId from clients

content/renderer/gpu/compositor_output_surface.h

Index: content/renderer/gpu/compositor_output_surface.h
diff --git a/content/renderer/gpu/compositor_output_surface.h b/content/renderer/gpu/compositor_output_surface.h
index 42e48c9455e720237eee97a5f74d246c31055e91..51e94ee3b499f8aa573dd62f7b2cfe5c095d9cd5 100644
--- a/content/renderer/gpu/compositor_output_surface.h
+++ b/content/renderer/gpu/compositor_output_surface.h
@@ -19,6 +19,7 @@
 #include "build/build_config.h"
 #include "cc/output/begin_frame_args.h"
 #include "cc/output/output_surface.h"
+#include "cc/surfaces/surface_id_allocator.h"
 #include "content/renderer/gpu/compositor_forwarding_message_filter.h"
 #include "ipc/ipc_sync_message_filter.h"
 
@@ -98,6 +99,11 @@ class CompositorOutputSurface
   scoped_refptr<CompositorOutputSurfaceProxy> output_surface_proxy_;
   scoped_refptr<IPC::SyncMessageFilter> message_sender_;
   scoped_refptr<FrameSwapMessageQueue> frame_swap_message_queue_;
+  cc::SurfaceIdAllocator allocator_;
+  cc::SurfaceId surface_id_;
+  gfx::Size current_surface_size_;
+  gfx::Size current_surface_size_in_dip_;
+  float current_scale_factor_;
   int routing_id_;
 };