Pull in various gpu/command_buffer fixes from chromium

gpu/config/gpu_switches.h

Index: gpu/config/gpu_switches.h
diff --git a/gpu/config/gpu_switches.h b/gpu/config/gpu_switches.h
new file mode 100644
index 0000000000000000000000000000000000000000..f6375ca06fe2ff30f23e40270c9f19dcb4d41668
--- /dev/null
+++ b/gpu/config/gpu_switches.h
@@ -0,0 +1,16 @@
+// 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.
+
+#ifndef GPU_CONFIG_GPU_SWITCHES_H_
+#define GPU_CONFIG_GPU_SWITCHES_H_
+
+#include "gpu/gpu_export.h"
+
+namespace switches {
+
+GPU_EXPORT extern const char kGpuDriverBugWorkarounds[];
+
+}  // namespace switches
+
+#endif  // GPU_CONFIG_GPU_SWITCHES_H_