Add a user pref in Settings to disable all GPU features.

chrome/browser/gpu/gpu_mode_manager.h

+// Copyright (c) 2013 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 CHROME_BROWSER_GPU_GPU_MODE_MANAGER_H_
+#define CHROME_BROWSER_GPU_GPU_MODE_MANAGER_H_
+
+#include "base/prefs/public/pref_change_registrar.h"
+
+class PrefRegistrySimple;
+
+class GpuModeManager {
+ public:
+  static void RegisterPrefs(PrefRegistrySimple* registry);
+
+  GpuModeManager();
+  ~GpuModeManager();
+
+ private:
+  bool IsGpuModePrefEnabled() const;
+
+  PrefChangeRegistrar pref_registrar_;
+
+  DISALLOW_COPY_AND_ASSIGN(GpuModeManager);
+};
+
+#endif  // CHROME_BROWSER_GPU_GPU_MODE_MANAGER_H_
+