gpu: Fix dependency cycle between service_sources and config_sources.

gpu/config/gpu_switches.cc

Index: gpu/config/gpu_switches.cc
diff --git a/chromecast/net/net_switches.h b/gpu/config/gpu_switches.cc
similarity index 55%
copy from chromecast/net/net_switches.h
copy to gpu/config/gpu_switches.cc
index dda9cac54fcd8ec8e8af35565fac0a3405cf1fc2..fdf9f0e180bebd44ce7e5b58e04f4208bfe0820b 100644
--- a/chromecast/net/net_switches.h
+++ b/gpu/config/gpu_switches.cc
@@ -2,13 +2,11 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef CHROMECAST_NET_NET_SWITCHES_H_
-#define CHROMECAST_NET_NET_SWITCHES_H_
+#include "gpu/config/gpu_switches.h"
 
 namespace switches {
 
-extern const char kConnectivityCheckUrl[];
+// Pass a set of GpuDriverBugWorkaroundType ids, seperated by ','.
+const char kGpuDriverBugWorkarounds[] = "gpu-driver-bug-workarounds";
 
 }  // namespace switches
-
-#endif  // CHROMECAST_NET_NET_SWITCHES_H_