app_shell: Use real audio preferences and save them to local state

This allows app_shell to support the chrome.audio extension API in the same
way that Chrome does.

* Introduce "local state" for device wide preferences
* Use a real AudioDevicesPrefHandlerImpl in app_shell

This also sets the default output volume for app_shell (for non-HDMI output)
to 75%, which is consistent with Chrome on Chrome OS.

BUG=442401
TEST=chromeos_unittests and app_shell_unittests for audio
TBR=yoz@chromium.org for adding a test data file to extensions/test/data

Review URL: https://codereview.chromium.org/816793002

Cr-Commit-Position: refs/heads/master@{#309138}

4 files changed, 31 insertions, 29 deletions

diff --git a/chromeos/audio/audio_devices_pref_handler.h b/chromeos/audio/audio_devices_pref_handler.h
index 53a3fce..aeb7b3d 100644
--- a/chromeos/audio/audio_devices_pref_handler.h
+++ b/chromeos/audio/audio_devices_pref_handler.h
@@ -22,6 +22,10 @@ struct AudioDevice;
 class CHROMEOS_EXPORT AudioDevicesPrefHandler
     : public base::RefCountedThreadSafe<AudioDevicesPrefHandler> {
  public:
+  // Integer because C++ does not allow static const double in header files.
+  static const int kDefaultOutputVolumePercent = 75;
+  static const int kDefaultHdmiOutputVolumePercent = 100;
+
   // Gets the audio output volume value from prefs for a device. Since we can
   // only have either a gain or a volume for a device (depending on whether it
   // is input or output), we don't really care which value it is.
diff --git a/chromeos/audio/audio_devices_pref_handler_impl.cc b/chromeos/audio/audio_devices_pref_handler_impl.cc
index 77987c7..d262369 100644
--- a/chromeos/audio/audio_devices_pref_handler_impl.cc
+++ b/chromeos/audio/audio_devices_pref_handler_impl.cc
@@ -18,9 +18,6 @@
 
 namespace {
 
-const double kDefaultOutputVolume = 75.0;
-const double kDefaultHDMIOutputVolume = 100.0;
-
 // Values used for muted preference.
 const int kPrefMuteOff = 0;
 const int kPrefMuteOn = 1;
@@ -50,7 +47,7 @@ namespace chromeos {
 double AudioDevicesPrefHandlerImpl::GetOutputVolumeValue(
     const AudioDevice* device) {
   if (!device)
-    return kDefaultOutputVolume;
+    return kDefaultOutputVolumePercent;
   else
     return GetVolumeGainPrefValue(*device);
 }
@@ -132,9 +129,9 @@ double AudioDevicesPrefHandlerImpl::GetVolumeGainPrefValue(
 double AudioDevicesPrefHandlerImpl::GetDeviceDefaultOutputVolume(
     const AudioDevice& device) {
   if (device.type == AUDIO_TYPE_HDMI)
-    return kDefaultHDMIOutputVolume;
+    return kDefaultHdmiOutputVolumePercent;
   else
-    return kDefaultOutputVolume;
+    return kDefaultOutputVolumePercent;
 }
 
 AudioDevicesPrefHandlerImpl::AudioDevicesPrefHandlerImpl(
@@ -194,7 +191,7 @@ void AudioDevicesPrefHandlerImpl::SaveDevicesVolumePref() {
                                    prefs::kAudioDevicesVolumePercent);
   base::DictionaryValue::Iterator it(*device_volume_settings_);
   while (!it.IsAtEnd()) {
-    double volume = kDefaultOutputVolume;
+    double volume = kDefaultOutputVolumePercent;
     bool success = it.value().GetAsDouble(&volume);
     DCHECK(success);
     dict_update->SetDouble(it.key(), volume);
@@ -242,7 +239,7 @@ void AudioDevicesPrefHandlerImpl::RegisterPrefs(
 
   // Register the legacy audio prefs for migration.
   registry->RegisterDoublePref(prefs::kAudioVolumePercent,
-                               kDefaultOutputVolume);
+                               kDefaultOutputVolumePercent);
   registry->RegisterIntegerPref(prefs::kAudioMute, kPrefMuteOff);
 }
 
diff --git a/chromeos/audio/audio_devices_pref_handler_stub.cc b/chromeos/audio/audio_devices_pref_handler_stub.cc
index 83b9aab..84810af 100644
--- a/chromeos/audio/audio_devices_pref_handler_stub.cc
+++ b/chromeos/audio/audio_devices_pref_handler_stub.cc
@@ -4,6 +4,7 @@
 
 #include "chromeos/audio/audio_devices_pref_handler_stub.h"
 
+#include "base/stl_util.h"
 #include "chromeos/audio/audio_device.h"
 
 namespace chromeos {
@@ -16,15 +17,16 @@ AudioDevicesPrefHandlerStub::~AudioDevicesPrefHandlerStub() {
 
 double AudioDevicesPrefHandlerStub::GetOutputVolumeValue(
     const AudioDevice* device) {
-  if (!device)
-    return 75.0;
+  if (!device || !ContainsKey(audio_device_volume_gain_map_, device->id))
+    return kDefaultOutputVolumePercent;
   return audio_device_volume_gain_map_[device->id];
 }
 
 double AudioDevicesPrefHandlerStub::GetInputGainValue(
     const AudioDevice* device) {
-  if (!device)
-    return 0.0;
+  // TODO(rkc): The default value for gain is wrong. http://crbug.com/442489
+  if (!device || !ContainsKey(audio_device_volume_gain_map_, device->id))
+    return 75.0;
   return audio_device_volume_gain_map_[device->id];
 }
 
diff --git a/chromeos/audio/audio_devices_pref_handler_stub.h b/chromeos/audio/audio_devices_pref_handler_stub.h
index 756038d..077f230 100644
--- a/chromeos/audio/audio_devices_pref_handler_stub.h
+++ b/chromeos/audio/audio_devices_pref_handler_stub.h
@@ -5,36 +5,35 @@
 #ifndef CHROMEOS_AUDIO_AUDIO_DEVICES_PREF_HANDLER_STUB_H_
 #define CHROMEOS_AUDIO_AUDIO_DEVICES_PREF_HANDLER_STUB_H_
 
-#include "chromeos/audio/audio_devices_pref_handler.h"
-
 #include <map>
 
-namespace chromeos {
+#include "base/macros.h"
+#include "chromeos/audio/audio_devices_pref_handler.h"
 
-struct AudioDevice;
+namespace chromeos {
 
 // Stub class for AudioDevicesPrefHandler, used for testing.
 class CHROMEOS_EXPORT AudioDevicesPrefHandlerStub
     : public AudioDevicesPrefHandler {
  public:
-  typedef std::map<uint64, bool> AudioDeviceMute;
-  typedef std::map<uint64, int> AudioDeviceVolumeGain;
+  using AudioDeviceMute = std::map<uint64_t, bool>;
+  using AudioDeviceVolumeGain = std::map<uint64_t, int>;
 
   AudioDevicesPrefHandlerStub();
 
-  virtual double GetOutputVolumeValue(const AudioDevice* device) override;
-  virtual double GetInputGainValue(const AudioDevice* device) override;
-  virtual void SetVolumeGainValue(const AudioDevice& device,
-                                  double value) override;
-  virtual bool GetMuteValue(const AudioDevice& device) override;
-  virtual void SetMuteValue(const AudioDevice& device, bool mute_on) override;
-  virtual bool GetAudioCaptureAllowedValue() override;
-  virtual bool GetAudioOutputAllowedValue() override;
-  virtual void AddAudioPrefObserver(AudioPrefObserver* observer) override;
-  virtual void RemoveAudioPrefObserver(AudioPrefObserver* observer) override;
+  // AudioDevicesPrefHandler:
+  double GetOutputVolumeValue(const AudioDevice* device) override;
+  double GetInputGainValue(const AudioDevice* device) override;
+  void SetVolumeGainValue(const AudioDevice& device, double value) override;
+  bool GetMuteValue(const AudioDevice& device) override;
+  void SetMuteValue(const AudioDevice& device, bool mute_on) override;
+  bool GetAudioCaptureAllowedValue() override;
+  bool GetAudioOutputAllowedValue() override;
+  void AddAudioPrefObserver(AudioPrefObserver* observer) override;
+  void RemoveAudioPrefObserver(AudioPrefObserver* observer) override;
 
  protected:
-  virtual ~AudioDevicesPrefHandlerStub();
+  ~AudioDevicesPrefHandlerStub() override;
 
  private:
   AudioDeviceMute audio_device_mute_map_;