Revert of Make lost context and error message callbacks on GpuControl go to client

ppapi/proxy/ppapi_command_buffer_proxy.cc

Index: ppapi/proxy/ppapi_command_buffer_proxy.cc
diff --git a/ppapi/proxy/ppapi_command_buffer_proxy.cc b/ppapi/proxy/ppapi_command_buffer_proxy.cc
index a9019b7add6c1f1f00f85157384889e4725cfa53..c96b44af5565dd35070541565b36c7ca10f60d95 100644
--- a/ppapi/proxy/ppapi_command_buffer_proxy.cc
+++ b/ppapi/proxy/ppapi_command_buffer_proxy.cc
@@ -241,11 +241,6 @@
   NOTREACHED();
 }
 
-void PpapiCommandBufferProxy::SetGpuControlClient(gpu::GpuControlClient*) {
-  // TODO(piman): The lost context callback skips past here and goes directly
-  // to the plugin instance. Make it more uniform and use the GpuControlClient.
-}
-
 gpu::Capabilities PpapiCommandBufferProxy::GetCapabilities() {
   return capabilities_;
 }