sync compositor: Reduce begin frame sync IPC overhead

content/renderer/android/synchronous_compositor_proxy.cc

 // Copyright 2015 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.
 
 #include "content/renderer/android/synchronous_compositor_proxy.h"
 
 #include "base/auto_reset.h"
 #include "base/command_line.h"
 #include "base/memory/shared_memory.h"
 #include "cc/ipc/cc_param_traits.h"
@@ skipping 114 matching lines @@
   params->need_invalidate_count = need_invalidate_count_;
   params->did_activate_pending_tree_count = did_activate_pending_tree_count_;
 }
 
 void SynchronousCompositorProxy::OnMessageReceived(
     const IPC::Message& message) {
   if (output_surface_ && output_surface_->OnMessageReceived(message))
     return;
 
   IPC_BEGIN_MESSAGE_MAP(SynchronousCompositorProxy, message)
-    IPC_MESSAGE_HANDLER(SyncCompositorMsg_SynchronizeRendererState,
-                        PopulateCommonParams)
     IPC_MESSAGE_HANDLER(SyncCompositorMsg_ComputeScroll, OnComputeScroll)
     IPC_MESSAGE_HANDLER_DELAY_REPLY(SyncCompositorMsg_DemandDrawHw,
                                     DemandDrawHw)
     IPC_MESSAGE_HANDLER(SyncCompositorMsg_SetSharedMemory, SetSharedMemory)
     IPC_MESSAGE_HANDLER(SyncCompositorMsg_ZeroSharedMemory, ZeroSharedMemory)
     IPC_MESSAGE_HANDLER_DELAY_REPLY(SyncCompositorMsg_DemandDrawSw,
                                     DemandDrawSw)
     IPC_MESSAGE_HANDLER(SyncCompositorMsg_ZoomBy, SynchronouslyZoomBy)
     IPC_MESSAGE_HANDLER(SyncCompositorMsg_SetScroll, SetScroll)
   IPC_END_MESSAGE_MAP()
@@ skipping 182 matching lines @@
 
 void SynchronousCompositorProxy::SetScroll(
     const gfx::ScrollOffset& new_total_scroll_offset) {
   if (total_scroll_offset_ == new_total_scroll_offset)
     return;
   total_scroll_offset_ = new_total_scroll_offset;
   input_handler_proxy_->SynchronouslySetRootScrollOffset(total_scroll_offset_);
 }
 
 }  // namespace content