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 58ad59a3cb57cbbbea44b0bbd8fcdac47d253876..605407b87151ec69c1db7e50ada7b8c76471bf30 100644
--- a/ppapi/proxy/ppapi_command_buffer_proxy.cc
+++ b/ppapi/proxy/ppapi_command_buffer_proxy.cc
@@ -241,6 +241,11 @@ void PpapiCommandBufferProxy::SignalQuery(uint32_t query,
   NOTREACHED();
 }
 
+void PpapiCommandBufferProxy::SetGpuControlClient(gpu::GpuControlClient*) {
+  // There's no concept of lost context or error message for this implementation
+  // of GpuControl, so we don't bother to store the client.
+}
+
 gpu::Capabilities PpapiCommandBufferProxy::GetCapabilities() {
   return capabilities_;
 }