Update from chromium https://crrev.com/301315

ui/gl/gpu_switching_observer.h

Index: ui/gl/gpu_switching_observer.h
diff --git a/ui/gl/gpu_switching_observer.h b/ui/gl/gpu_switching_observer.h
new file mode 100644
index 0000000000000000000000000000000000000000..ed85d8a0d8e6ef4daf495481aa1d50bb6322c200
--- /dev/null
+++ b/ui/gl/gpu_switching_observer.h
@@ -0,0 +1,20 @@
+// Copyright 2014 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 UI_GL_GPU_SWITCHING_OBSERVER_H_
+#define UI_GL_GPU_SWITCHING_OBSERVER_H_
+
+#include "ui/gl/gl_export.h"
+
+namespace ui {
+
+class GL_EXPORT GpuSwitchingObserver {
+ public:
+  // Called for any observer when the system switches to a different GPU.
+  virtual void OnGpuSwitched() {};
+};
+
+}  // namespace ui
+
+#endif  // UI_GL_GPU_SWITCHING_OBSERVER_H_