Implemented new fence syncs which replaces the old sync points.

content/common/gpu/gpu_channel.cc

Index: content/common/gpu/gpu_channel.cc
diff --git a/content/common/gpu/gpu_channel.cc b/content/common/gpu/gpu_channel.cc
index 7b0593ebbc72ea7943657e20653f66aab8be3875..46a6f43bfc6f61045eb55adaaa4a7b96f8d9652c 100644
--- a/content/common/gpu/gpu_channel.cc
+++ b/content/common/gpu/gpu_channel.cc
@@ -806,6 +806,8 @@ bool GpuChannel::OnControlMessageReceived(const IPC::Message& msg) {
                         OnCreateOffscreenCommandBuffer)
     IPC_MESSAGE_HANDLER(GpuChannelMsg_DestroyCommandBuffer,
                         OnDestroyCommandBuffer)
+    IPC_MESSAGE_HANDLER(GpuChannelMsg_Nop,
+                        OnNop)
     IPC_MESSAGE_HANDLER_DELAY_REPLY(GpuMsg_CreateJpegDecoder,
                                     OnCreateJpegDecoder)
     IPC_MESSAGE_UNHANDLED(handled = false)
@@ -1021,6 +1023,8 @@ void GpuChannel::OnCreateJpegDecoder(int32 route_id, IPC::Message* reply_msg) {
   jpeg_decoder_->AddClient(route_id, reply_msg);
 }
 
+void GpuChannel::OnNop() {}
+
 void GpuChannel::CacheShader(const std::string& key,
                              const std::string& shader) {
   gpu_channel_manager_->Send(