sync compositor: Reduce begin frame sync IPC overhead

content/renderer/android/synchronous_compositor_filter.h

Index: content/renderer/android/synchronous_compositor_filter.h
diff --git a/content/renderer/android/synchronous_compositor_filter.h b/content/renderer/android/synchronous_compositor_filter.h
index c22e094f6f27711c490b306ffb58cb863d6b7ec8..54e44828f480b2143f5c353ff1b558d698f0f524 100644
--- a/content/renderer/android/synchronous_compositor_filter.h
+++ b/content/renderer/android/synchronous_compositor_filter.h
@@ -8,6 +8,7 @@
 #include <stdint.h>
 
 #include <memory>
+#include <vector>
 
 #include "base/containers/scoped_ptr_hash_map.h"
 #include "base/macros.h"
@@ -24,6 +25,7 @@ class SynchronousInputHandlerProxy;
 namespace content {
 
 class SynchronousCompositorProxy;
+struct SyncCompositorCommonRendererParams;
 
 class SynchronousCompositorFilter
     : public IPC::MessageFilter,
@@ -79,6 +81,9 @@ class SynchronousCompositorFilter
   void UnregisterObjects(int routing_id);
   void RemoveEntryIfNeeded(int routing_id);
   SynchronousCompositorProxy* FindProxy(int routing_id);
+  void OnSynchronizeRendererState(
+      const std::vector<int>& routing_ids,
+      std::vector<SyncCompositorCommonRendererParams>* out);
 
   const scoped_refptr<base::SingleThreadTaskRunner> compositor_task_runner_;