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

chrome/browser/gpu/gpu_mode_manager.cc

+// 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.
+
+#include "chrome/browser/gpu/gpu_mode_manager.h"
+
+#include "base/bind.h"
+#include "base/prefs/pref_registry_simple.h"
+#include "base/prefs/pref_service.h"
+#include "chrome/browser/browser_process.h"
+#include "chrome/common/pref_names.h"
+#include "content/public/browser/gpu_data_manager.h"
+
+// static
+void GpuModeManager::RegisterPrefs(PrefRegistrySimple* registry) {
+  registry->RegisterBooleanPref(
+      prefs::kHardwareAccelerationModeEnabled, true);
+}
+
+GpuModeManager::GpuModeManager() {
+  CHECK(g_browser_process != NULL);

[Lei Zhang, 2013/03/08 23:29:10]

Probably don't need this. If |g_browser_process| is NULL, you'll crash on the
next line, you'll know what happened.

[Zhenyao Mo, 2013/03/09 00:15:45]

Done.

+  if (g_browser_process->local_state()) {  // Skip for unit tests
+    pref_registrar_.Init(g_browser_process->local_state());
+    pref_registrar_.Add(

[Lei Zhang, 2013/03/08 23:29:10]

Do you need this when OnGpuModeEnabledPrefChanged doesn't do anything? If you do
need it, can you use DoNothing() from base/bind_helpers.h instead?

[Zhenyao Mo, 2013/03/09 00:15:45]

I do need this, otherwise Settings page won't load, claiming lacking of a
handler for the pref.  Change to DoNothing().

+        prefs::kHardwareAccelerationModeEnabled,
+        base::Bind(&GpuModeManager::OnGpuModeEnabledPrefChanged,
+                   base::Unretained(this)));
+
+    if (!IsGpuModePrefEnabled()) {
+      content::GpuDataManager* gpu_data_manager =
+          content::GpuDataManager::GetInstance();
+      DCHECK(gpu_data_manager);
+      gpu_data_manager->DisableHardwareAcceleration();
+    }
+  }
+}
+
+GpuModeManager::~GpuModeManager() {
+}
+
+void GpuModeManager::OnGpuModeEnabledPrefChanged() {
+  // Do nothing. The pref change takes effect after chrome restarts.
+}
+
+bool GpuModeManager::IsGpuModePrefEnabled() const {
+  PrefService* service = g_browser_process->local_state();
+  DCHECK(service);
+  return service->GetBoolean(
+      prefs::kHardwareAccelerationModeEnabled);
+}
+