13 files changed, 601 insertions, 0 deletions

diff --git a/chromeos/chromeos.gyp b/chromeos/chromeos.gyp
index 127d6eb..78eee8b 100644
--- a/chromeos/chromeos.gyp
+++ b/chromeos/chromeos.gyp
@@ -55,6 +55,8 @@
         'dbus/bluetooth_out_of_band_client.h',
         'dbus/bluetooth_property.cc',
         'dbus/bluetooth_property.h',
+        'dbus/cras_audio_client.cc',
+        'dbus/cras_audio_client.h',
         'dbus/cros_disks_client.cc',
         'dbus/cros_disks_client.h',
         'dbus/cryptohome_client.cc',
@@ -146,6 +148,8 @@
         'dbus/system_clock_client.h',
         'dbus/update_engine_client.cc',
         'dbus/update_engine_client.h',
+        'dbus/volume_state.cc',
+        'dbus/volume_state.h',
         'disks/disk_mount_manager.cc',
         'disks/disk_mount_manager.h',
         'display/output_configurator.cc',
@@ -277,6 +281,8 @@
         'dbus/mock_bluetooth_node_client.h',
         'dbus/mock_bluetooth_out_of_band_client.cc',
         'dbus/mock_bluetooth_out_of_band_client.h',
+        'dbus/mock_cras_audio_client.cc',
+        'dbus/mock_cras_audio_client.h',
         'dbus/mock_cros_disks_client.cc',
         'dbus/mock_cros_disks_client.h',
         'dbus/mock_cryptohome_client.cc',
diff --git a/chromeos/dbus/cras_audio_client.cc b/chromeos/dbus/cras_audio_client.cc
new file mode 100644
index 0000000..9e39fef
--- /dev/null
+++ b/chromeos/dbus/cras_audio_client.cc
@@ -0,0 +1,360 @@
+// 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 "chromeos/dbus/cras_audio_client.h"
+
+#include "base/bind.h"
+#include "dbus/bus.h"
+#include "dbus/message.h"
+#include "dbus/object_path.h"
+#include "dbus/object_proxy.h"
+#include "third_party/cros_system_api/dbus/service_constants.h"
+
+namespace {
+}  // namespace
+
+namespace chromeos {
+
+// The CrasAudioClient implementation used in production.
+class CrasAudioClientImpl : public CrasAudioClient {
+ public:
+  explicit CrasAudioClientImpl(dbus::Bus* bus)
+      : cras_proxy_(NULL),
+        weak_ptr_factory_(this) {
+    cras_proxy_ = bus->GetObjectProxy(
+        cras::kCrasServiceName,
+        dbus::ObjectPath(cras::kCrasServicePath));
+
+    // Monitor the D-Bus signal for output volume change.
+    cras_proxy_->ConnectToSignal(
+        cras::kCrasControlInterface,
+        cras::kOutputVolumeChanged,
+        base::Bind(&CrasAudioClientImpl::OutputVolumeChangedReceived,
+                   weak_ptr_factory_.GetWeakPtr()),
+        base::Bind(&CrasAudioClientImpl::SignalConnected,
+                   weak_ptr_factory_.GetWeakPtr()));
+
+    // Monitor the D-Bus signal for output mute change.
+    cras_proxy_->ConnectToSignal(
+        cras::kCrasControlInterface,
+        cras::kOutputMuteChanged,
+        base::Bind(&CrasAudioClientImpl::OutputMuteChangedReceived,
+                   weak_ptr_factory_.GetWeakPtr()),
+        base::Bind(&CrasAudioClientImpl::SignalConnected,
+                   weak_ptr_factory_.GetWeakPtr()));
+
+    // Monitor the D-Bus signal for input gain change.
+    cras_proxy_->ConnectToSignal(
+        cras::kCrasControlInterface,
+        cras::kInputGainChanged,
+        base::Bind(&CrasAudioClientImpl::InputGainChangedReceived,
+                   weak_ptr_factory_.GetWeakPtr()),
+        base::Bind(&CrasAudioClientImpl::SignalConnected,
+                   weak_ptr_factory_.GetWeakPtr()));
+
+    // Monitor the D-Bus signal for input mute change.
+    cras_proxy_->ConnectToSignal(
+        cras::kCrasControlInterface,
+        cras::kInputMuteChanged,
+        base::Bind(&CrasAudioClientImpl::InputMuteChangedReceived,
+                   weak_ptr_factory_.GetWeakPtr()),
+        base::Bind(&CrasAudioClientImpl::SignalConnected,
+                   weak_ptr_factory_.GetWeakPtr()));
+
+    // Monitor the D-Bus signal for nodes change.
+    cras_proxy_->ConnectToSignal(
+        cras::kCrasControlInterface,
+        cras::kNodesChanged,
+        base::Bind(&CrasAudioClientImpl::NodesChangedReceived,
+                   weak_ptr_factory_.GetWeakPtr()),
+        base::Bind(&CrasAudioClientImpl::SignalConnected,
+                   weak_ptr_factory_.GetWeakPtr()));
+
+    // Monitor the D-Bus signal for active output node change.
+    cras_proxy_->ConnectToSignal(
+        cras::kCrasControlInterface,
+        cras::kActiveOutputNodeChanged,
+        base::Bind(&CrasAudioClientImpl::ActiveOutputNodeChangedReceived,
+                   weak_ptr_factory_.GetWeakPtr()),
+        base::Bind(&CrasAudioClientImpl::SignalConnected,
+                   weak_ptr_factory_.GetWeakPtr()));
+
+    // Monitor the D-Bus signal for active input node change.
+    cras_proxy_->ConnectToSignal(
+        cras::kCrasControlInterface,
+        cras::kActiveInputNodeChanged,
+        base::Bind(&CrasAudioClientImpl::ActiveInputNodeChangedReceived,
+                   weak_ptr_factory_.GetWeakPtr()),
+        base::Bind(&CrasAudioClientImpl::SignalConnected,
+                   weak_ptr_factory_.GetWeakPtr()));
+  }
+
+  virtual ~CrasAudioClientImpl() {
+  }
+
+  // CrasAudioClient overrides:
+  virtual void AddObserver(Observer* observer) OVERRIDE {
+    observers_.AddObserver(observer);
+  }
+
+  virtual void RemoveObserver(Observer* observer) OVERRIDE {
+    observers_.RemoveObserver(observer);
+  }
+
+  virtual bool HasObserver(Observer* observer) OVERRIDE {
+    return observers_.HasObserver(observer);
+  }
+
+  virtual void GetVolumeState(const GetVolumeStateCallback& callback) OVERRIDE {
+    dbus::MethodCall method_call(cras::kCrasControlInterface,
+                                 cras::kGetVolumeState);
+    cras_proxy_->CallMethod(
+        &method_call,
+        dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
+        base::Bind(&CrasAudioClientImpl::OnGetVolumeState,
+                   weak_ptr_factory_.GetWeakPtr(), callback));
+  }
+
+  virtual void SetOutputVolume(int32 volume) OVERRIDE {
+    dbus::MethodCall method_call(cras::kCrasControlInterface,
+                                 cras::kSetOutputVolume);
+    dbus::MessageWriter writer(&method_call);
+    writer.AppendInt32(volume);
+    cras_proxy_->CallMethod(
+        &method_call,
+        dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
+        dbus::ObjectProxy::EmptyResponseCallback());
+  }
+
+  virtual void SetOutputMute(bool mute_on) OVERRIDE {
+    dbus::MethodCall method_call(cras::kCrasControlInterface,
+                                 cras::kSetOutputMute);
+    dbus::MessageWriter writer(&method_call);
+    writer.AppendBool(mute_on);
+    cras_proxy_->CallMethod(
+        &method_call,
+        dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
+        dbus::ObjectProxy::EmptyResponseCallback());
+  }
+
+  virtual void SetInputGain(int32 input_gain) OVERRIDE {
+    dbus::MethodCall method_call(cras::kCrasControlInterface,
+                                 cras::kSetInputGain);
+    dbus::MessageWriter writer(&method_call);
+    writer.AppendInt32(input_gain);
+    cras_proxy_->CallMethod(
+        &method_call,
+        dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
+        dbus::ObjectProxy::EmptyResponseCallback());
+  }
+
+  virtual void SetInputMute(bool mute_on) OVERRIDE {
+    dbus::MethodCall method_call(cras::kCrasControlInterface,
+                                 cras::kSetInputMute);
+    dbus::MessageWriter writer(&method_call);
+    writer.AppendBool(mute_on);
+    cras_proxy_->CallMethod(
+        &method_call,
+        dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
+        dbus::ObjectProxy::EmptyResponseCallback());
+  }
+
+  virtual void SetActiveOutputNode(uint64 node_id) OVERRIDE {
+    dbus::MethodCall method_call(cras::kCrasControlInterface,
+                                 cras::kSetActiveOutputNode);
+    dbus::MessageWriter writer(&method_call);
+    writer.AppendUint64(node_id);
+    cras_proxy_->CallMethod(
+        &method_call,
+        dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
+        dbus::ObjectProxy::EmptyResponseCallback());
+  }
+
+  virtual void SetActiveInputNode(uint64 node_id) OVERRIDE {
+    dbus::MethodCall method_call(cras::kCrasControlInterface,
+                                 cras::kSetActiveInputNode);
+    dbus::MessageWriter writer(&method_call);
+    writer.AppendUint64(node_id);
+    cras_proxy_->CallMethod(
+        &method_call,
+        dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
+        dbus::ObjectProxy::EmptyResponseCallback());
+  }
+
+ private:
+  // Called when the cras signal is initially connected.
+  void SignalConnected(const std::string& interface_name,
+                       const std::string& signal_name,
+                       bool success) {
+    LOG_IF(ERROR, !success)
+        << "Failed to connect to cras signal:" << signal_name;
+  }
+
+  // Called when a OutputVolumeChanged signal is received.
+  void OutputVolumeChangedReceived(dbus::Signal* signal) {
+    dbus::MessageReader reader(signal);
+    int32 volume;
+    if (!reader.PopInt32(&volume)) {
+      LOG(ERROR) << "Error reading signal from cras:"
+                 << signal->ToString();
+    }
+    FOR_EACH_OBSERVER(Observer, observers_, OutputVolumeChanged(volume));
+  }
+
+  // Called when a OutputMuteChanged signal is received.
+  void OutputMuteChangedReceived(dbus::Signal* signal) {
+    dbus::MessageReader reader(signal);
+    bool mute;
+    if (!reader.PopBool(&mute)) {
+      LOG(ERROR) << "Error reading signal from cras:"
+                 << signal->ToString();
+    }
+    FOR_EACH_OBSERVER(Observer, observers_, OutputMuteChanged(mute));
+  }
+
+  // Called when a InputGainChanged signal is received.
+  void InputGainChangedReceived(dbus::Signal* signal) {
+    dbus::MessageReader reader(signal);
+    int32 gain;
+    if (!reader.PopInt32(&gain)) {
+      LOG(ERROR) << "Error reading signal from cras:"
+                 << signal->ToString();
+    }
+    FOR_EACH_OBSERVER(Observer, observers_, InputGainChanged(gain));
+  }
+
+  // Called when a InputMuteChanged signal is received.
+  void InputMuteChangedReceived(dbus::Signal* signal) {
+    dbus::MessageReader reader(signal);
+    bool mute;
+    if (!reader.PopBool(&mute)) {
+      LOG(ERROR) << "Error reading signal from cras:"
+                 << signal->ToString();
+    }
+    FOR_EACH_OBSERVER(Observer, observers_, InputMuteChanged(mute));
+  }
+
+  void NodesChangedReceived(dbus::Signal* signal) {
+    FOR_EACH_OBSERVER(Observer, observers_, NodesChanged());
+  }
+
+  void ActiveOutputNodeChangedReceived(dbus::Signal* signal) {
+    dbus::MessageReader reader(signal);
+    uint64 node_id;
+    if (!reader.PopUint64(&node_id)) {
+      LOG(ERROR) << "Error reading signal from cras:"
+          << signal->ToString();
+    }
+    FOR_EACH_OBSERVER(Observer, observers_, ActiveOutputNodeChanged(node_id));
+  }
+
+  void ActiveInputNodeChangedReceived(dbus::Signal* signal) {
+    dbus::MessageReader reader(signal);
+    uint64 node_id;
+    if (!reader.PopUint64(&node_id)) {
+      LOG(ERROR) << "Error reading signal from cras:"
+          << signal->ToString();
+    }
+    FOR_EACH_OBSERVER(Observer, observers_, ActiveInputNodeChanged(node_id));
+  }
+
+  void OnGetVolumeState(const GetVolumeStateCallback& callback,
+                        dbus::Response* response) {
+    if (!response) {
+      LOG(ERROR) << "Error calling " << cras::kGetVolumeState;
+      return;
+    }
+
+    dbus::MessageReader reader(response);
+    VolumeState volume_state;
+    if (!reader.PopInt32(&volume_state.output_volume) ||
+        !reader.PopBool(&volume_state.output_mute) ||
+        !reader.PopInt32(&volume_state.input_gain) ||
+        !reader.PopBool(&volume_state.input_mute)) {
+      LOG(ERROR) << "Error reading response from cras: "
+                 << response->ToString();
+    }
+    callback.Run(volume_state);
+  }
+
+  dbus::ObjectProxy* cras_proxy_;
+  ObserverList<Observer> observers_;
+
+  // Note: This should remain the last member so it'll be destroyed and
+  // invalidate its weak pointers before any other members are destroyed.
+  base::WeakPtrFactory<CrasAudioClientImpl> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(CrasAudioClientImpl);
+};
+
+// The CrasAudioClient implementation used on Linux desktop,
+// which does nothing.
+class CrasAudioClientStubImpl : public CrasAudioClient {
+ public:
+  CrasAudioClientStubImpl() {
+    LOG(ERROR) << "CrasAudioClientStubImpl is created";
+  }
+  ~CrasAudioClientStubImpl() {}
+
+  // CrasAudioClient overrides:
+  // TODO(jennyz): Implement the observers and callbacks in the stub for UI
+  // testing.
+  virtual void AddObserver(Observer* observer) OVERRIDE {}
+  virtual void RemoveObserver(Observer* observer) OVERRIDE {}
+  virtual bool HasObserver(Observer* observer) OVERRIDE { return false; }
+  virtual void GetVolumeState(const GetVolumeStateCallback& callback) OVERRIDE {
+  }
+  virtual void SetOutputVolume(int32 volume) OVERRIDE {}
+  virtual void SetOutputMute(bool mute_on) OVERRIDE {}
+  virtual void SetInputGain(int32 input_gain) OVERRIDE {}
+  virtual void SetInputMute(bool mute_on) OVERRIDE {}
+  virtual void SetActiveOutputNode(uint64 node_id) OVERRIDE {}
+  virtual void SetActiveInputNode(uint64 node_id) OVERRIDE {}
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(CrasAudioClientStubImpl);
+};
+
+CrasAudioClient::Observer::~Observer() {
+}
+
+void CrasAudioClient::Observer::OutputVolumeChanged(int32 volume) {
+}
+
+void CrasAudioClient::Observer::OutputMuteChanged(bool mute_on) {
+}
+
+void CrasAudioClient::Observer::InputGainChanged(int gain) {
+}
+
+void CrasAudioClient::Observer::InputMuteChanged(bool mute_on) {
+}
+
+void CrasAudioClient::Observer::NodesChanged() {
+}
+
+void CrasAudioClient::Observer::ActiveOutputNodeChanged(uint64 node_id){
+}
+
+void CrasAudioClient::Observer::ActiveInputNodeChanged(uint64 node_id) {
+}
+
+CrasAudioClient::CrasAudioClient() {
+}
+
+CrasAudioClient::~CrasAudioClient() {
+}
+
+// static
+CrasAudioClient* CrasAudioClient::Create(
+    DBusClientImplementationType type,
+    dbus::Bus* bus) {
+  if (type == REAL_DBUS_CLIENT_IMPLEMENTATION) {
+    return new CrasAudioClientImpl(bus);
+  }
+  DCHECK_EQ(STUB_DBUS_CLIENT_IMPLEMENTATION, type);
+  return new CrasAudioClientStubImpl();
+}
+
+}  // namespace chromeos
diff --git a/chromeos/dbus/cras_audio_client.h b/chromeos/dbus/cras_audio_client.h
new file mode 100644
index 0000000..969bfb0
--- /dev/null
+++ b/chromeos/dbus/cras_audio_client.h
@@ -0,0 +1,88 @@
+// 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 CHROMEOS_DBUS_CRAS_AUDIO_CLIENT_H_
+#define CHROMEOS_DBUS_CRAS_AUDIO_CLIENT_H_
+
+#include "base/callback.h"
+#include "base/observer_list.h"
+#include "chromeos/chromeos_export.h"
+#include "chromeos/dbus/dbus_client_implementation_type.h"
+#include "chromeos/dbus/volume_state.h"
+
+namespace dbus {
+class Bus;
+}  // namespace
+
+namespace chromeos {
+
+// CrasAudioClient is used to communicate with the cras audio dbus interface.
+class CHROMEOS_EXPORT CrasAudioClient {
+ public:
+  // Interface for observing changes from the cras audio changes.
+  class Observer {
+   public:
+    // Called when audio output device volume changed.
+    virtual void OutputVolumeChanged(int volume);
+    virtual void OutputMuteChanged(bool mute_on);
+    virtual void InputGainChanged(int gain);
+    virtual void InputMuteChanged(bool mute_on);
+    virtual void NodesChanged();
+    virtual void ActiveOutputNodeChanged(uint64 node_id);
+    virtual void ActiveInputNodeChanged(uint64 node_id);
+
+   protected:
+    virtual ~Observer();
+  };
+
+  virtual ~CrasAudioClient();
+
+  // Adds and removes the observer.
+  virtual void AddObserver(Observer* observer) = 0;
+  virtual void RemoveObserver(Observer* observer) = 0;
+  // Returns true if this object has the given observer.
+  virtual bool HasObserver(Observer* observer) = 0;
+
+  // GetVolumeStateCallback is used for GetVolumeState method. It receives
+  // 1 argument, |volume_state| which containing both input and  output volume
+  // state data.
+  typedef base::Callback<void(const VolumeState&)> GetVolumeStateCallback;
+
+  // Gets the volume state, asynchronously.
+  virtual void GetVolumeState(const GetVolumeStateCallback& callback) = 0;
+
+  // Sets output volume to |volume|, in the range of [0, 100].
+  virtual void  SetOutputVolume(int32 volume) = 0;
+
+  // Sets output mute state to |mute_on| value.
+  virtual void SetOutputMute(bool mute_on) = 0;
+
+  // Sets input gain to |input_gain|. |input_gain| is specified in dBFS * 100.
+  virtual void SetInputGain(int32 input_gain) = 0;
+
+  // Sets input mute state to |mute_on| value.
+  virtual void SetInputMute(bool mute_on) = 0;
+
+  // Sets the active output noe to |node_id|.
+  virtual void SetActiveOutputNode(uint64 node_id) = 0;
+
+  // Sets the active input noe to |node_id|.
+  virtual void SetActiveInputNode(uint64 node_id) = 0;
+
+  // Creates the instance.
+  static CrasAudioClient* Create(DBusClientImplementationType type,
+                                 dbus::Bus* bus);
+
+ protected:
+  // Create() should be used instead.
+  CrasAudioClient();
+
+ private:
+
+  DISALLOW_COPY_AND_ASSIGN(CrasAudioClient);
+};
+
+}  // namespace chromeos
+
+#endif  // CHROMEOS_DBUS_CRAS_AUDIO_CLIENT_H_
diff --git a/chromeos/dbus/dbus_thread_manager.cc b/chromeos/dbus/dbus_thread_manager.cc
index 4325505..cc286b5 100644
--- a/chromeos/dbus/dbus_thread_manager.cc
+++ b/chromeos/dbus/dbus_thread_manager.cc
@@ -17,6 +17,7 @@
 #include "chromeos/dbus/bluetooth_manager_client.h"
 #include "chromeos/dbus/bluetooth_node_client.h"
 #include "chromeos/dbus/bluetooth_out_of_band_client.h"
+#include "chromeos/dbus/cras_audio_client.h"
 #include "chromeos/dbus/cros_disks_client.h"
 #include "chromeos/dbus/cryptohome_client.h"
 #include "chromeos/dbus/dbus_client_implementation_type.h"
@@ -99,6 +100,8 @@ class DBusThreadManagerImpl : public DBusThreadManager {
         client_type_, system_bus_.get(), bluetooth_device_client_.get()));
     bluetooth_out_of_band_client_.reset(BluetoothOutOfBandClient::Create(
         client_type_, system_bus_.get()));
+    cras_audio_client_.reset(CrasAudioClient::Create(
+        client_type_, system_bus_.get()));
     cros_disks_client_.reset(
         CrosDisksClient::Create(client_type_, system_bus_.get()));
     cryptohome_client_.reset(
@@ -262,6 +265,10 @@ class DBusThreadManagerImpl : public DBusThreadManager {
     return bluetooth_out_of_band_client_.get();
   }
 
+  virtual CrasAudioClient* GetCrasAudioClient() OVERRIDE {
+    return cras_audio_client_.get();
+  }
+
   virtual CrosDisksClient* GetCrosDisksClient() OVERRIDE {
     return cros_disks_client_.get();
   }
@@ -419,6 +426,7 @@ class DBusThreadManagerImpl : public DBusThreadManager {
   scoped_ptr<BluetoothManagerClient> bluetooth_manager_client_;
   scoped_ptr<BluetoothNodeClient> bluetooth_node_client_;
   scoped_ptr<BluetoothOutOfBandClient> bluetooth_out_of_band_client_;
+  scoped_ptr<CrasAudioClient> cras_audio_client_;
   scoped_ptr<CrosDisksClient> cros_disks_client_;
   scoped_ptr<CryptohomeClient> cryptohome_client_;
   scoped_ptr<DebugDaemonClient> debug_daemon_client_;
diff --git a/chromeos/dbus/dbus_thread_manager.h b/chromeos/dbus/dbus_thread_manager.h
index e34a234..0002ebb 100644
--- a/chromeos/dbus/dbus_thread_manager.h
+++ b/chromeos/dbus/dbus_thread_manager.h
@@ -32,6 +32,7 @@ class BluetoothInputClient;
 class BluetoothManagerClient;
 class BluetoothNodeClient;
 class BluetoothOutOfBandClient;
+class CrasAudioClient;
 class CrosDisksClient;
 class CryptohomeClient;
 class DebugDaemonClient;
@@ -130,6 +131,7 @@ class CHROMEOS_EXPORT DBusThreadManager {
   virtual BluetoothManagerClient* GetBluetoothManagerClient() = 0;
   virtual BluetoothNodeClient* GetBluetoothNodeClient() = 0;
   virtual BluetoothOutOfBandClient* GetBluetoothOutOfBandClient() = 0;
+  virtual CrasAudioClient* GetCrasAudioClient() = 0;
   virtual CrosDisksClient* GetCrosDisksClient() = 0;
   virtual CryptohomeClient* GetCryptohomeClient() = 0;
   virtual DebugDaemonClient* GetDebugDaemonClient() = 0;
diff --git a/chromeos/dbus/mock_cras_audio_client.cc b/chromeos/dbus/mock_cras_audio_client.cc
new file mode 100644
index 0000000..31f21e5
--- /dev/null
+++ b/chromeos/dbus/mock_cras_audio_client.cc
@@ -0,0 +1,13 @@
+// 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 "chromeos/dbus/mock_cras_audio_client.h"
+
+
+namespace chromeos {
+
+MockCrasAudioClient::MockCrasAudioClient() {}
+MockCrasAudioClient::~MockCrasAudioClient() {}
+
+}  // namespace chromeos
diff --git a/chromeos/dbus/mock_cras_audio_client.h b/chromeos/dbus/mock_cras_audio_client.h
new file mode 100644
index 0000000..25e6a24
--- /dev/null
+++ b/chromeos/dbus/mock_cras_audio_client.h
@@ -0,0 +1,35 @@
+// 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 CHROMEOS_DBUS_MOCK_CRAS_AUDIO_CLIENT_H_
+#define CHROMEOS_DBUS_MOCK_CRAS_AUDIO_CLIENT_H_
+
+#include "chromeos/dbus/cras_audio_client.h"
+#include "testing/gmock/include/gmock/gmock.h"
+
+namespace chromeos {
+
+class MockCrasAudioClient : public CrasAudioClient {
+ public:
+  MockCrasAudioClient();
+  virtual ~MockCrasAudioClient();
+
+  MOCK_METHOD1(AddObserver, void(Observer*));
+  MOCK_METHOD1(RemoveObserver, void(Observer*));
+  MOCK_METHOD1(HasObserver, bool(Observer*));
+  MOCK_METHOD1(GetVolumeState, void(const GetVolumeStateCallback&));
+  MOCK_METHOD1(SetOutputVolume, void(int32));
+  MOCK_METHOD1(SetOutputMute, void(bool));
+  MOCK_METHOD1(SetInputGain, void(int32));
+  MOCK_METHOD1(SetInputMute, void(bool));
+  MOCK_METHOD1(SetActiveOutputNode, void(uint64));
+  MOCK_METHOD1(SetActiveInputNode, void(uint64));
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(MockCrasAudioClient);
+};
+
+}  // namespace chromeos
+
+#endif  // CHROMEOS_DBUS_MOCK_CRAS_AUDIO_CLIENT_H_
diff --git a/chromeos/dbus/mock_dbus_thread_manager.cc b/chromeos/dbus/mock_dbus_thread_manager.cc
index a9cfc63..f3dbdc6 100644
--- a/chromeos/dbus/mock_dbus_thread_manager.cc
+++ b/chromeos/dbus/mock_dbus_thread_manager.cc
@@ -11,6 +11,7 @@
 #include "chromeos/dbus/mock_bluetooth_manager_client.h"
 #include "chromeos/dbus/mock_bluetooth_node_client.h"
 #include "chromeos/dbus/mock_bluetooth_out_of_band_client.h"
+#include "chromeos/dbus/mock_cras_audio_client.h"
 #include "chromeos/dbus/mock_cros_disks_client.h"
 #include "chromeos/dbus/mock_cryptohome_client.h"
 #include "chromeos/dbus/mock_debug_daemon_client.h"
@@ -49,6 +50,7 @@ MockDBusThreadManager::MockDBusThreadManager()
       mock_bluetooth_manager_client_(new MockBluetoothManagerClient),
       mock_bluetooth_node_client_(new MockBluetoothNodeClient),
       mock_bluetooth_out_of_band_client_(new MockBluetoothOutOfBandClient),
+      mock_cras_audio_client_(new MockCrasAudioClient),
       mock_cros_disks_client_(new MockCrosDisksClient),
       mock_cryptohome_client_(new MockCryptohomeClient),
       mock_debugdaemon_client_(new MockDebugDaemonClient),
@@ -87,6 +89,8 @@ MockDBusThreadManager::MockDBusThreadManager()
       .WillRepeatedly(Return(mock_bluetooth_node_client_.get()));
   EXPECT_CALL(*this, GetBluetoothOutOfBandClient())
       .WillRepeatedly(Return(mock_bluetooth_out_of_band_client_.get()));
+  EXPECT_CALL(*this, GetCrasAudioClient())
+      .WillRepeatedly(Return(mock_cras_audio_client()));
   EXPECT_CALL(*this, GetCrosDisksClient())
       .WillRepeatedly(Return(mock_cros_disks_client()));
   EXPECT_CALL(*this, GetCryptohomeClient())
@@ -159,6 +163,12 @@ MockDBusThreadManager::MockDBusThreadManager()
       .WillRepeatedly(Return(power_policy_controller_.get()));
 
   // These observers calls are used in ChromeBrowserMainPartsChromeos.
+  EXPECT_CALL(*mock_cras_audio_client_.get(), AddObserver(_))
+      .Times(AnyNumber());
+  EXPECT_CALL(*mock_cras_audio_client_.get(), RemoveObserver(_))
+      .Times(AnyNumber());
+  EXPECT_CALL(*mock_cras_audio_client_.get(), HasObserver(_))
+      .Times(AnyNumber());
   EXPECT_CALL(*mock_session_manager_client_.get(), AddObserver(_))
       .Times(AnyNumber());
   EXPECT_CALL(*mock_session_manager_client_.get(), RemoveObserver(_))
diff --git a/chromeos/dbus/mock_dbus_thread_manager.h b/chromeos/dbus/mock_dbus_thread_manager.h
index 12a4906e..ef60c8a 100644
--- a/chromeos/dbus/mock_dbus_thread_manager.h
+++ b/chromeos/dbus/mock_dbus_thread_manager.h
@@ -26,6 +26,7 @@ class MockBluetoothInputClient;
 class MockBluetoothManagerClient;
 class MockBluetoothNodeClient;
 class MockBluetoothOutOfBandClient;
+class MockCrasAudioClient;
 class MockCrosDisksClient;
 class MockCryptohomeClient;
 class MockDebugDaemonClient;
@@ -70,6 +71,7 @@ class MockDBusThreadManager : public DBusThreadManager {
   MOCK_METHOD0(GetBluetoothManagerClient, BluetoothManagerClient*(void));
   MOCK_METHOD0(GetBluetoothNodeClient, BluetoothNodeClient*(void));
   MOCK_METHOD0(GetBluetoothOutOfBandClient, BluetoothOutOfBandClient*(void));
+  MOCK_METHOD0(GetCrasAudioClient, CrasAudioClient*(void));
   MOCK_METHOD0(GetCrosDisksClient, CrosDisksClient*(void));
   MOCK_METHOD0(GetCryptohomeClient, CryptohomeClient*(void));
   MOCK_METHOD0(GetDebugDaemonClient, DebugDaemonClient*(void));
@@ -125,6 +127,9 @@ class MockDBusThreadManager : public DBusThreadManager {
   MockBluetoothOutOfBandClient* mock_bluetooth_out_of_band_client() {
     return mock_bluetooth_out_of_band_client_.get();
   }
+  MockCrasAudioClient* mock_cras_audio_client() {
+    return mock_cras_audio_client_.get();
+  }
   MockCrosDisksClient* mock_cros_disks_client() {
     return mock_cros_disks_client_.get();
   }
@@ -207,6 +212,7 @@ class MockDBusThreadManager : public DBusThreadManager {
   scoped_ptr<MockBluetoothManagerClient> mock_bluetooth_manager_client_;
   scoped_ptr<MockBluetoothNodeClient> mock_bluetooth_node_client_;
   scoped_ptr<MockBluetoothOutOfBandClient> mock_bluetooth_out_of_band_client_;
+  scoped_ptr<MockCrasAudioClient> mock_cras_audio_client_;
   scoped_ptr<MockCrosDisksClient> mock_cros_disks_client_;
   scoped_ptr<MockCryptohomeClient> mock_cryptohome_client_;
   scoped_ptr<MockDebugDaemonClient> mock_debugdaemon_client_;
diff --git a/chromeos/dbus/mock_dbus_thread_manager_without_gmock.cc b/chromeos/dbus/mock_dbus_thread_manager_without_gmock.cc
index 5e9b866..49c5bbe 100644
--- a/chromeos/dbus/mock_dbus_thread_manager_without_gmock.cc
+++ b/chromeos/dbus/mock_dbus_thread_manager_without_gmock.cc
@@ -82,6 +82,11 @@ BluetoothNodeClient*
   return NULL;
 }
 
+CrasAudioClient* MockDBusThreadManagerWithoutGMock::GetCrasAudioClient() {
+  NOTIMPLEMENTED();
+  return NULL;
+}
+
 CrosDisksClient* MockDBusThreadManagerWithoutGMock::GetCrosDisksClient() {
   NOTIMPLEMENTED();
   return NULL;
diff --git a/chromeos/dbus/mock_dbus_thread_manager_without_gmock.h b/chromeos/dbus/mock_dbus_thread_manager_without_gmock.h
index 70530bb..04853ed 100644
--- a/chromeos/dbus/mock_dbus_thread_manager_without_gmock.h
+++ b/chromeos/dbus/mock_dbus_thread_manager_without_gmock.h
@@ -46,6 +46,7 @@ class MockDBusThreadManagerWithoutGMock : public DBusThreadManager {
   virtual BluetoothInputClient* GetBluetoothInputClient() OVERRIDE;
   virtual BluetoothManagerClient* GetBluetoothManagerClient() OVERRIDE;
   virtual BluetoothNodeClient* GetBluetoothNodeClient() OVERRIDE;
+  virtual CrasAudioClient* GetCrasAudioClient() OVERRIDE;
   virtual CrosDisksClient* GetCrosDisksClient() OVERRIDE;
   virtual CryptohomeClient* GetCryptohomeClient() OVERRIDE;
   virtual DebugDaemonClient* GetDebugDaemonClient() OVERRIDE;
diff --git a/chromeos/dbus/volume_state.cc b/chromeos/dbus/volume_state.cc
new file mode 100644
index 0000000..da0ff13
--- /dev/null
+++ b/chromeos/dbus/volume_state.cc
@@ -0,0 +1,40 @@
+// 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 "chromeos/dbus/volume_state.h"
+
+#include "base/format_macros.h"
+#include "base/stringprintf.h"
+
+namespace chromeos {
+
+VolumeState::VolumeState()
+    : output_volume(0),
+      output_mute(false),
+      input_gain(0),
+      input_mute(false) {
+}
+
+std::string VolumeState::ToString() const {
+  std::string result;
+  base::StringAppendF(&result,
+                      "output_volume = %d ",
+                      output_volume);
+  base::StringAppendF(&result,
+                      "output_mute = %s ",
+                      output_mute ? "true" : "false");
+  base::StringAppendF(&result,
+                      "output_mute = %s ",
+                      output_mute ? "true" : "false");
+  base::StringAppendF(&result,
+                      "input_gain = %d ",
+                      input_gain);
+  base::StringAppendF(&result,
+                      "input_mute = %s ",
+                      input_mute ? "true" : "false");
+
+  return result;
+}
+
+}  // namespace chromeos
diff --git a/chromeos/dbus/volume_state.h b/chromeos/dbus/volume_state.h
new file mode 100644
index 0000000..7fafd6e
--- /dev/null
+++ b/chromeos/dbus/volume_state.h
@@ -0,0 +1,27 @@
+// 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 CHROMEOS_DBUS_VOLUME_STATE_H_
+#define CHROMEOS_DBUS_VOLUME_STATE_H_
+
+#include <string>
+
+#include "base/basictypes.h"
+#include "chromeos/chromeos_export.h"
+
+namespace chromeos {
+
+struct CHROMEOS_EXPORT VolumeState {
+  int32 output_volume;
+  bool output_mute;
+  int32 input_gain;
+  bool input_mute;
+
+  VolumeState();
+  std::string ToString() const;
+};
+
+}  // namespace chromeos
+
+#endif  // CHROMEOS_DBUS_VOLUME_STATE_H_