Handle audio node stable device ID change

chromeos/audio/audio_devices_pref_handler_impl_unittest.cc

 // 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.
 
 #include "chromeos/audio/audio_devices_pref_handler_impl.h"
 
 #include <stdint.h>
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "chromeos/audio/audio_device.h"
 #include "chromeos/audio/audio_devices_pref_handler.h"
 #include "chromeos/chromeos_pref_names.h"
 #include "chromeos/dbus/audio_node.h"
+#include "components/prefs/scoped_user_pref_update.h"
 #include "components/prefs/testing_pref_service.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace chromeos {
 
+using testing::Values;
+
+const uint64_t kPresetInputId = 10001;
+const uint64_t kHeadphoneId = 10002;
 const uint64_t kInternalMicId = 10003;
-const uint64_t kHeadphoneId = 10002;
+const uint64_t kPresetOutputId = 10004;
+const uint64_t kUSBMicId = 10005;
 const uint64_t kHDMIOutputId = 10006;
-const uint64_t kUSBMicId = 10004;
 const uint64_t kOtherTypeOutputId = 90001;
 const uint64_t kOtherTypeInputId = 90002;
 
-const AudioDevice kInternalMic(AudioNode(true,
-                                         kInternalMicId,
-                                         kInternalMicId,
-                                         "Fake Mic",
-                                         "INTERNAL_MIC",
-                                         "Internal Mic",
-                                         false,
-                                         0));
-const AudioDevice kUSBMic(AudioNode(true,
-                                    kUSBMicId,
-                                    kUSBMicId,
-                                    "Fake USB Mic",
-                                    "USB",
-                                    "USB Microphone",
-                                    false,
-                                    0));
+const char kPresetInputDeprecatedPrefKey[] = "10001 : 1";
+const char kPresetOutputDeprecatedPrefKey[] = "10004 : 0";
 
-const AudioDevice kHeadphone(AudioNode(false,
-                                       kHeadphoneId,
-                                       kHeadphoneId,
-                                       "Fake Headphone",
-                                       "HEADPHONE",
-                                       "Headphone",
-                                       false,
-                                       0));
+const double kDefaultSoundLevel = 75.0;
 
-const AudioDevice kHDMIOutput(AudioNode(false,
-                                        kHDMIOutputId,
-                                        kHDMIOutputId,
-                                        "HDMI output",
-                                        "HDMI",
-                                        "HDMI output",
-                                        false,
-                                        0));
+const struct {
+  bool active;
+  bool activate_by_user;
+  double sound_level;
+  bool mute;
+} kPresetState = {true, true, 25.2, true};
 
-const AudioDevice kInputDeviceWithSpecialCharacters(
-    AudioNode(true,
-              kOtherTypeInputId,
-              kOtherTypeInputId,
-              "Fake ~!@#$%^&*()_+`-=<>?,./{}|[]\\\\Mic",
-              "SOME_OTHER_TYPE",
-              "Other Type Input Device",
-              true,
-              0));
+struct AudioNodeInfo {
+  bool is_input;
+  uint64_t id;
+  const char* const device_name;
+  const char* const type;
+  const char* const name;
+};
 
-const AudioDevice kOutputDeviceWithSpecialCharacters(
-    AudioNode(false,
-              kOtherTypeOutputId,
-              kOtherTypeOutputId,
-              "Fake ~!@#$%^&*()_+`-=<>?,./{}|[]\\\\Headphone",
-              "SOME_OTHER_TYPE",
-              "Other Type Output Device",
-              false,
-              0));
+const AudioNodeInfo kPresetInput = {true, kPresetInputId, "Fake input",
+                                    "INTERNAL_MIC", "Preset fake input"};
 
-class AudioDevicesPrefHandlerTest : public testing::Test {
+const AudioNodeInfo kInternalMic = {true, kInternalMicId, "Fake Mic",
+                                    "INTERNAL_MIC", "Internal Mic"};
+
+const AudioNodeInfo kUSBMic = {true, kUSBMicId, "Fake USB Mic", "USB",
+                               "USB Microphone"};
+
+const AudioNodeInfo kPresetOutput = {false, kPresetOutputId, "Fake output",
+                                     "HEADPHONE", "Preset fake output"};
+
+const AudioNodeInfo kHeadphone = {false, kHeadphoneId, "Fake Headphone",
+                                  "HEADPHONE", "Headphone"};
+
+const AudioNodeInfo kHDMIOutput = {false, kHDMIOutputId, "HDMI output", "HDMI",
+                                   "HDMI output"};
+
+const AudioNodeInfo kInputDeviceWithSpecialCharacters = {
+    true, kOtherTypeInputId, "Fake ~!@#$%^&*()_+`-=<>?,./{}|[]\\\\Mic",
+    "SOME_OTHER_TYPE", "Other Type Input Device"};
+
+const AudioNodeInfo kOutputDeviceWithSpecialCharacters = {
+    false, kOtherTypeOutputId, "Fake ~!@#$%^&*()_+`-=<>?,./{}|[]\\\\Headphone",
+    "SOME_OTHER_TYPE", "Other Type Output Device"};
+
+AudioDevice CreateAudioDevice(const AudioNodeInfo& info, int version) {
+  return AudioDevice(AudioNode(
+      info.is_input, info.id, version == 2, info.id /* stable_device_id_v1 */,
+      version == 1 ? 0 : info.id ^ 0xFF /* stable_device_id_v2 */,
+      info.device_name, info.type, info.name, false, 0));
+}
+
+// Test param determines whether the test should test input or output devices
+// true -> input devices
+// false -> output_devices
+class AudioDevicesPrefHandlerTest : public testing::TestWithParam<bool> {
  public:
   AudioDevicesPrefHandlerTest() {}
   ~AudioDevicesPrefHandlerTest() override {}
 
   void SetUp() override {
     pref_service_.reset(new TestingPrefServiceSimple());
     AudioDevicesPrefHandlerImpl::RegisterPrefs(pref_service_->registry());
+
+    // Set the preset pref values directly, to ensure it doesn't depend on pref
+    // handler implementation.
+    // This has to be done before audio_pref_hander_ is created, so the values
+    // are set when pref value sets up its internal state.
+    std::string preset_key = GetPresetDeviceDeprecatedPrefKey();
+    {
+      DictionaryPrefUpdate update(pref_service_.get(),
+                                  prefs::kAudioDevicesState);
+      base::DictionaryValue* pref = update.Get();
+      std::unique_ptr<base::DictionaryValue> state(new base::DictionaryValue());
+      state->SetBoolean("active", kPresetState.active);
+      state->SetBoolean("activate_by_user", kPresetState.activate_by_user);
+      pref->Set(preset_key, std::move(state));
+    }
+
+    {
+      DictionaryPrefUpdate update(pref_service_.get(),
+                                  prefs::kAudioDevicesVolumePercent);
+      base::DictionaryValue* pref = update.Get();
+      pref->SetDouble(preset_key, kPresetState.sound_level);
+    }
+
+    {
+      DictionaryPrefUpdate update(pref_service_.get(),
+                                  prefs::kAudioDevicesMute);
+      base::DictionaryValue* pref = update.Get();
+      pref->SetInteger(preset_key, kPresetState.mute ? 1 : 0);
+    }
+
     audio_pref_handler_ = new AudioDevicesPrefHandlerImpl(pref_service_.get());
   }
 
   void TearDown() override { audio_pref_handler_ = NULL; }
 
  protected:
+  void ReloadPrefHandler() {
+    audio_pref_handler_ = new AudioDevicesPrefHandlerImpl(pref_service_.get());
+  }
+
+  AudioDevice GetDevice(int version) {

[jennyz, 2016/12/09 23:52:18]

Can we rename it to GetDeviceWithVersion()? More self explained.

[tbarzic, 2016/12/10 02:35:08]

Done.

+    return CreateAudioDevice(GetParam() ? kInternalMic : kHeadphone, version);
+  }
+
+  std::string GetPresetDeviceDeprecatedPrefKey() {
+    return GetParam() ? kPresetInputDeprecatedPrefKey
+                      : kPresetOutputDeprecatedPrefKey;
+  }
+
+  AudioDevice GetPresetDevice(int version) {

[jennyz, 2016/12/09 23:52:18]

ditto

[tbarzic, 2016/12/10 02:35:08]

Done.

+    return CreateAudioDevice(GetParam() ? kPresetInput : kPresetOutput,
+                             version);
+  }
+
+  AudioDevice GetSecondaryDevice(int version) {

[jennyz, 2016/12/09 23:52:18]

ditto

[tbarzic, 2016/12/10 02:35:08]

Done.

+    return CreateAudioDevice(GetParam() ? kUSBMic : kHDMIOutput, version);
+  }
+
+  AudioDevice GetDeviceWithSpecialCharacters(int version) {

[jennyz, 2016/12/09 23:52:18]

ditto

[tbarzic, 2016/12/10 02:35:08]

Done.

+    return CreateAudioDevice(GetParam() ? kInputDeviceWithSpecialCharacters
+                                        : kOutputDeviceWithSpecialCharacters,
+                             version);
+  }
+
+  double GetSoundLevelValue(const AudioDevice& device) {
+    return GetParam() ? audio_pref_handler_->GetInputGainValue(&device)
+                      : audio_pref_handler_->GetOutputVolumeValue(&device);
+  }
+
+  void SetSoundLevelValue(const AudioDevice& device, double value) {
+    return audio_pref_handler_->SetVolumeGainValue(device, value);
+  }
+
+  void SetDeviceState(const AudioDevice& device,
+                      bool active,
+                      bool activated_by_user) {
+    audio_pref_handler_->SetDeviceActive(device, active, activated_by_user);
+  }
+
+  bool DeviceStateExists(const AudioDevice& device) {
+    bool unused;
+    return audio_pref_handler_->GetDeviceActive(device, &unused, &unused);
+  }
+
+  void ExpectDeviceStateEquals(const AudioDevice& device,
+                               bool expect_active,
+                               bool expect_activated_by_user) {
+    bool active = false;
+    bool activated_by_user = false;
+    ASSERT_TRUE(audio_pref_handler_->GetDeviceActive(device, &active,
+                                                     &activated_by_user))
+        << " value for device " << device.id << " not found.";
+    EXPECT_EQ(expect_active, active) << " device " << device.id;
+    EXPECT_EQ(expect_activated_by_user, activated_by_user) << " device "
+                                                           << device.id;
+  }
+
+  bool GetMute(const AudioDevice& device) {
+    return audio_pref_handler_->GetMuteValue(device);
+  }
+
+  void SetMute(const AudioDevice& device, bool value) {
+    audio_pref_handler_->SetMuteValue(device, value);
+  }
+
   scoped_refptr<AudioDevicesPrefHandler> audio_pref_handler_;
   std::unique_ptr<TestingPrefServiceSimple> pref_service_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(AudioDevicesPrefHandlerTest);
 };
 
-TEST_F(AudioDevicesPrefHandlerTest, TestDefaultValues) {
+INSTANTIATE_TEST_CASE_P(Input, AudioDevicesPrefHandlerTest, Values(true));
+INSTANTIATE_TEST_CASE_P(Output, AudioDevicesPrefHandlerTest, Values(false));
+
+TEST_P(AudioDevicesPrefHandlerTest, TestDefaultValuesV1) {
+  AudioDevice device = GetDevice(1);
+  AudioDevice secondary_device = GetSecondaryDevice(1);
+
   // TODO(rkc): Once the bug with default preferences is fixed, fix this test
   // also. http://crbug.com/442489
-  EXPECT_EQ(75.0, audio_pref_handler_->GetInputGainValue(&kInternalMic));
-  EXPECT_EQ(75.0, audio_pref_handler_->GetOutputVolumeValue(&kHeadphone));
-  EXPECT_EQ(75.0, audio_pref_handler_->GetOutputVolumeValue(&kHDMIOutput));
-  bool active, activate_by_user;
-  EXPECT_FALSE(audio_pref_handler_->GetDeviceActive(kInternalMic, &active,
-                                                    &activate_by_user));
-  EXPECT_FALSE(audio_pref_handler_->GetDeviceActive(kHeadphone, &active,
-                                                    &activate_by_user));
-  EXPECT_FALSE(audio_pref_handler_->GetDeviceActive(kHDMIOutput, &active,
-                                                    &activate_by_user));
+  EXPECT_EQ(kDefaultSoundLevel, GetSoundLevelValue(device));
+  EXPECT_EQ(kDefaultSoundLevel, GetSoundLevelValue(secondary_device));
+
+  EXPECT_FALSE(DeviceStateExists(device));
+  EXPECT_FALSE(DeviceStateExists(secondary_device));
+
+  EXPECT_FALSE(GetMute(device));
+  EXPECT_FALSE(GetMute(secondary_device));
 }
 
-TEST_F(AudioDevicesPrefHandlerTest, PrefsRegistered) {
+TEST_P(AudioDevicesPrefHandlerTest, TestDefaultValuesV2) {
+  AudioDevice device = GetDevice(2);
+  AudioDevice secondary_device = GetSecondaryDevice(2);
+
+  // TODO(rkc): Once the bug with default preferences is fixed, fix this test
+  // also. http://crbug.com/442489
+  EXPECT_EQ(kDefaultSoundLevel, GetSoundLevelValue(device));
+  EXPECT_EQ(kDefaultSoundLevel, GetSoundLevelValue(secondary_device));
+
+  EXPECT_FALSE(DeviceStateExists(device));
+  EXPECT_FALSE(DeviceStateExists(secondary_device));
+
+  EXPECT_FALSE(GetMute(device));
+  EXPECT_FALSE(GetMute(secondary_device));
+}
+
+TEST_P(AudioDevicesPrefHandlerTest, PrefsRegistered) {
   // The standard audio prefs are registered.
   EXPECT_TRUE(pref_service_->FindPreference(prefs::kAudioDevicesVolumePercent));
   EXPECT_TRUE(pref_service_->FindPreference(prefs::kAudioDevicesMute));
   EXPECT_TRUE(pref_service_->FindPreference(prefs::kAudioOutputAllowed));
   EXPECT_TRUE(pref_service_->FindPreference(prefs::kAudioVolumePercent));
   EXPECT_TRUE(pref_service_->FindPreference(prefs::kAudioMute));
   EXPECT_TRUE(pref_service_->FindPreference(prefs::kAudioDevicesState));
 }
 
-TEST_F(AudioDevicesPrefHandlerTest, TestBasicInputOutputDevices) {
-  audio_pref_handler_->SetVolumeGainValue(kInternalMic, 13.37);
-  EXPECT_EQ(13.37, audio_pref_handler_->GetInputGainValue(&kInternalMic));
-  audio_pref_handler_->SetVolumeGainValue(kHeadphone, 47.28);
-  EXPECT_EQ(47.28, audio_pref_handler_->GetOutputVolumeValue(&kHeadphone));
+TEST_P(AudioDevicesPrefHandlerTest, SoundLevel) {
+  AudioDevice device = GetDevice(2);
+  SetSoundLevelValue(device, 13.37);
+  EXPECT_EQ(13.37, GetSoundLevelValue(device));
 }
 
-TEST_F(AudioDevicesPrefHandlerTest, TestSpecialCharactersInDeviceNames) {
-  audio_pref_handler_->SetVolumeGainValue(kInputDeviceWithSpecialCharacters,
-                                          73.31);
-  audio_pref_handler_->SetVolumeGainValue(kOutputDeviceWithSpecialCharacters,
-                                          85.92);
+TEST_P(AudioDevicesPrefHandlerTest, SoundLevelMigratedFromV1StableId) {
+  AudioDevice device_v1 = GetPresetDevice(1);
+  AudioDevice device_v2 = GetPresetDevice(2);
 
-  EXPECT_EQ(73.31, audio_pref_handler_->GetInputGainValue(
-      &kInputDeviceWithSpecialCharacters));
-  EXPECT_EQ(85.92, audio_pref_handler_->GetOutputVolumeValue(
-      &kOutputDeviceWithSpecialCharacters));
+  EXPECT_EQ(kPresetState.sound_level, GetSoundLevelValue(device_v1));
+  EXPECT_EQ(kPresetState.sound_level, GetSoundLevelValue(device_v2));
+  // Test that v1 entry does not exist after migration - the method should
+  // return default value

[jennyz, 2016/12/09 23:52:18]

Add a line to verify kDefaultSoundLevel is not equal to
kPresetState.sound_level.

[tbarzic, 2016/12/10 02:35:08]

Done.

+  EXPECT_EQ(kDefaultSoundLevel, GetSoundLevelValue(device_v1));
+
+  // Test that values are persisted when audio pref handler is reset.
+  ReloadPrefHandler();
+  EXPECT_EQ(kDefaultSoundLevel, GetSoundLevelValue(device_v1));
+  EXPECT_EQ(kPresetState.sound_level, GetSoundLevelValue(device_v2));
 }
 
-TEST_F(AudioDevicesPrefHandlerTest, TestDeviceStates) {
-  audio_pref_handler_->SetDeviceActive(kInternalMic, true, true);
-  bool active = false;
-  bool activate_by_user = false;
-  EXPECT_TRUE(audio_pref_handler_->GetDeviceActive(kInternalMic, &active,
-                                                   &activate_by_user));
-  EXPECT_TRUE(active);
-  EXPECT_TRUE(activate_by_user);
+TEST_P(AudioDevicesPrefHandlerTest, SettingV2DeviceSoundLevelRemovesV1Entry) {
+  AudioDevice device_v1 = GetDevice(1);
+  AudioDevice device_v2 = GetDevice(2);
 
-  audio_pref_handler_->SetDeviceActive(kHeadphone, true, false);
-  EXPECT_TRUE(audio_pref_handler_->GetDeviceActive(kHeadphone, &active,
-                                                   &activate_by_user));
-  EXPECT_TRUE(active);
-  EXPECT_FALSE(activate_by_user);
+  SetSoundLevelValue(device_v1, 13.37);
+  EXPECT_EQ(13.37, GetSoundLevelValue(device_v1));
 
-  audio_pref_handler_->SetDeviceActive(kHDMIOutput, false, false);
-  EXPECT_TRUE(audio_pref_handler_->GetDeviceActive(kHDMIOutput, &active,
-                                                   &activate_by_user));
-  EXPECT_FALSE(active);
+  SetSoundLevelValue(device_v2, 13.38);
+  EXPECT_EQ(kDefaultSoundLevel, GetSoundLevelValue(device_v1));
+  EXPECT_EQ(13.38, GetSoundLevelValue(device_v2));
 
-  // Device not exist in device state prefs.
-  EXPECT_FALSE(audio_pref_handler_->GetDeviceActive(kUSBMic, &active,
-                                                    &activate_by_user));
+  // Test that values are persisted when audio pref handler is reset.
+  ReloadPrefHandler();
+  EXPECT_EQ(kDefaultSoundLevel, GetSoundLevelValue(device_v1));
+  EXPECT_EQ(13.38, GetSoundLevelValue(device_v2));
+}
+
+TEST_P(AudioDevicesPrefHandlerTest, MigrateFromGlobalSoundLevelPref) {
+  pref_service_->SetDouble(prefs::kAudioVolumePercent, 13.37);
+
+  // For devices with v1 stable device id.
+  EXPECT_EQ(13.37, GetSoundLevelValue(GetDevice(1)));
+  EXPECT_EQ(13.37, GetSoundLevelValue(GetDevice(2)));
+
+  // For devices with v2 stable id.
+  EXPECT_EQ(13.37, GetSoundLevelValue(GetSecondaryDevice(2)));
+}
+
+TEST_P(AudioDevicesPrefHandlerTest, Mute) {
+  AudioDevice device = GetDevice(2);
+  SetMute(device, true);
+  EXPECT_TRUE(GetMute(device));
+
+  SetMute(device, false);
+  EXPECT_FALSE(GetMute(device));
+}
+
+TEST_P(AudioDevicesPrefHandlerTest, MuteMigratedFromV1StableId) {
+  AudioDevice device_v1 = GetPresetDevice(1);
+  AudioDevice device_v2 = GetPresetDevice(2);
+
+  EXPECT_EQ(kPresetState.mute, GetMute(device_v1));
+  EXPECT_EQ(kPresetState.mute, GetMute(device_v2));
+  // Test that v1 entry does not exist after migration - the method should
+  // return default value

[jennyz, 2016/12/09 23:52:18]

Add a line to verify kPresetState.mute is true, which is different that the
default mute value (false).

[tbarzic, 2016/12/10 02:35:08]

Done.

+  EXPECT_FALSE(GetMute(device_v1));
+
+  // Test that values are persisted when audio pref handler is reset.
+  ReloadPrefHandler();
+  EXPECT_FALSE(GetMute(device_v1));
+  EXPECT_EQ(kPresetState.mute, GetMute(device_v2));
+}
+
+TEST_P(AudioDevicesPrefHandlerTest, SettingV2DeviceMuteRemovesV1Entry) {
+  AudioDevice device_v1 = GetDevice(1);
+  AudioDevice device_v2 = GetDevice(2);
+
+  SetMute(device_v1, true);
+  EXPECT_TRUE(GetMute(device_v1));
+
+  SetMute(device_v2, true);
+  EXPECT_FALSE(GetMute(device_v1));
+  EXPECT_TRUE(GetMute(device_v2));
+
+  // Test that values are persisted when audio pref handler is reset.
+  ReloadPrefHandler();
+  EXPECT_FALSE(GetMute(device_v1));
+  EXPECT_TRUE(GetMute(device_v2));
+}
+
+TEST_P(AudioDevicesPrefHandlerTest, MigrateFromGlobalMutePref) {
+  pref_service_->SetInteger(prefs::kAudioMute, true);
+
+  // For devices with v1 stable device id.
+  EXPECT_TRUE(GetMute(GetDevice(1)));
+  EXPECT_TRUE(GetMute(GetDevice(2)));
+
+  // For devices with v2 stable id.
+  EXPECT_TRUE(GetMute(GetSecondaryDevice(2)));
+}
+
+TEST_P(AudioDevicesPrefHandlerTest, TestSpecialCharactersInDeviceNames) {
+  AudioDevice device = GetDeviceWithSpecialCharacters(2);
+  SetSoundLevelValue(device, 73.31);
+  EXPECT_EQ(73.31, GetSoundLevelValue(device));
+
+  SetMute(device, true);
+  EXPECT_TRUE(GetMute(device));
+
+  SetDeviceState(device, true, true);
+  ExpectDeviceStateEquals(device, true, true);
+}
+
+TEST_P(AudioDevicesPrefHandlerTest, TestDeviceStates) {
+  AudioDevice device = GetDevice(2);
+  SetDeviceState(device, true, true);
+  ExpectDeviceStateEquals(device, true, true);
+
+  SetDeviceState(device, true, false);
+  ExpectDeviceStateEquals(device, true, false);
+
+  SetDeviceState(device, false, false);
+  ExpectDeviceStateEquals(device, false, false);
+
+  AudioDevice secondary_device = GetSecondaryDevice(2);
+  EXPECT_FALSE(DeviceStateExists(secondary_device));
+}
+
+TEST_P(AudioDevicesPrefHandlerTest, TestDeviceStatesMigrateFromV1StableId) {
+  AudioDevice device_v1 = GetPresetDevice(1);
+  AudioDevice device_v2 = GetPresetDevice(2);
+
+  ExpectDeviceStateEquals(device_v1, kPresetState.active,
+                          kPresetState.activate_by_user);
+  ExpectDeviceStateEquals(device_v2, kPresetState.active,
+                          kPresetState.activate_by_user);
+  EXPECT_FALSE(DeviceStateExists(device_v1));
+
+  // Test that values are persisted when audio pref handler is reset.
+  ReloadPrefHandler();
+  EXPECT_FALSE(DeviceStateExists(device_v1));
+  ExpectDeviceStateEquals(device_v2, kPresetState.active,
+                          kPresetState.activate_by_user);
+}
+
+TEST_P(AudioDevicesPrefHandlerTest, TestSettingV2DeviceStateRemovesV1Entry) {
+  AudioDevice device_v1 = GetDevice(1);
+  AudioDevice device_v2 = GetDevice(2);
+
+  SetDeviceState(device_v1, true, true);
+  ExpectDeviceStateEquals(device_v1, true, true);
+
+  SetDeviceState(device_v2, false, false);
+  EXPECT_FALSE(DeviceStateExists(device_v1));
+  ExpectDeviceStateEquals(device_v2, false, false);
+
+  // Test that values are persisted when audio pref handler is reset.
+  ReloadPrefHandler();
+  EXPECT_FALSE(DeviceStateExists(device_v1));
+  ExpectDeviceStateEquals(device_v2, false, false);
 }
 
 }  // namespace chromeos