Added command buffer implementation of WebGL which runs in the sandbox....

chrome/gpu/gpu_thread.cc

Index: chrome/gpu/gpu_thread.cc
===================================================================
--- chrome/gpu/gpu_thread.cc	(revision 42776)
+++ chrome/gpu/gpu_thread.cc	(working copy)
@@ -40,6 +40,8 @@
   IPC_BEGIN_MESSAGE_MAP_EX(GpuThread, msg, msg_is_ok)
     IPC_MESSAGE_HANDLER(GpuMsg_EstablishChannel,
                         OnEstablishChannel)
+    IPC_MESSAGE_HANDLER(GpuMsg_Synchronize,
+                        OnSynchronize)
     IPC_MESSAGE_HANDLER(GpuMsg_NewRenderWidgetHostView,
                         OnNewRenderWidgetHostView)
   IPC_END_MESSAGE_MAP_EX()
@@ -79,6 +81,10 @@
   Send(new GpuHostMsg_ChannelEstablished(channel_handle));
 }
 
+void GpuThread::OnSynchronize(int renderer_id) {
+  Send(new GpuHostMsg_SynchronizeReply(renderer_id));
+}
+
 void GpuThread::OnNewRenderWidgetHostView(GpuNativeWindowHandle parent_window,
                                           int32 routing_id) {
   // The GPUView class' lifetime is controlled by the host, which will send a