Add GL strings to CastSysInfo interface and use to configure GPU

chromecast/base/cast_sys_info_dummy.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 "chromecast/base/cast_sys_info_dummy.h"
 
 namespace chromecast {
 
 CastSysInfoDummy::CastSysInfoDummy() {
 }
@@ skipping 46 matching lines @@
 }
 
 std::string CastSysInfoDummy::GetWifiInterface() {
   return "";
 }
 
 std::string CastSysInfoDummy::GetApInterface() {
   return "";
 }
 
+std::string CastSysInfoDummy::GetGpuVendor() {
+  return "";
+}
+
+std::string CastSysInfoDummy::GetGpuModel() {
+  return "";
+}
+
 }  // namespace chromecast