Final cleanup pass over audio device API

extensions/common/api/audio.idl

 // 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.
 
 // The <code>chrome.audio</code> API is provided to allow users to
 // get information about and control the audio devices attached to the
 // system. This API is currently only implemented for ChromeOS.
 namespace audio {
 
   // Type of stream an audio device provides.
@@ skipping 63 matching lines @@
     // True if this is the current active device.
     boolean isActive;
     // True if this is muted.
     boolean isMuted;
     // The sound level of the device, volume for output, gain for input.
     long level;
     // The stable/persisted device id string when available.
     DOMString? stableDeviceId;
   };
 
+  dictionary DeviceFilter {
+    // If set, only audio devices whose stream type is included in this list
+    // will satisfy the filter.
+    StreamType[]? streamTypes;
+
+    // If set, only audio devices whose active state matches this value will
+    // satisfy the filter.
+    boolean? isActive;
+  };
+
   dictionary DeviceProperties {
     // True if this is muted.
     [deprecated="Use $(ref:setMute) to set mute state."] boolean? isMuted;
+
     // If this is an output device then this field indicates the output volume.
     // If this is an input device then this field is ignored.
-    double? volume;
+    [deprecated="Use |level| to set output volume."] double? volume;
+
     // If this is an input device then this field indicates the input gain.
     // If this is an output device then this field is ignored.
-    double? gain;
+    [deprecated="Use |level| to set input gain."] double? gain;
+ 
+    // <p>
+    //   The audio device's desired sound level. Defaults to the device's
+    //   current sound level.
+    // </p> 
+    // <p>If used with audio input device, represents audio device gain.</p>
+    // <p>If used with audio output device, represents audio device volume.</p>
+    long? level;
   };
 
   dictionary DeviceIdLists {
     // <p>List of input devices specified by their ID.</p>
     // <p>To indicate input devices should be unaffected, leave this property
     //   unset.</p>
     DOMString[]? input;
 
     // <p>List of output devices specified by their ID.</p>
     // <p>To indicate output devices should be unaffected, leave this property
     //   unset.</p>
     DOMString[]? output;
   };
 
   dictionary MuteChangedEvent {
     // The type of the stream for which the mute value changed. The updated mute
     // value applies to all devices with this stream type.
     StreamType streamType;
 
     // Whether or not the stream is now muted.
     boolean isMuted;
   };
 
+  dictionary LevelChangedEvent {
+    // ID of device whose sound level has changed.
+    DOMString deviceId;
+
+    // The device's new sound level.
+    long level;
+  };
+
   callback GetInfoCallback = void(OutputDeviceInfo[] outputInfo,
                                   InputDeviceInfo[] inputInfo);
+  callback GetDevicesCallback = void(AudioDeviceInfo[] devices);
+  callback GetMuteCallback = void(boolean value);
   callback EmptyCallback = void();
-  callback GetMuteCallback = void(boolean value);
 
   interface Functions {
     // Gets the information of all audio output and input devices.
     static void getInfo(GetInfoCallback callback);
 
+    // Gets a list of audio devices filtered based on |filter|.
+    // |filter|: Device properties by which to filter the list of returned
+    //     audio devices. Use <code>{}</code> to get all available audio
+    //     devices.
+    // |callback|: Reports the requested list of audio devices. 
+    static void getDevices(DeviceFilter filter, GetDevicesCallback callback);
+
     // Sets lists of active input and/or output devices.
     // |ids|: <p>Specifies IDs of devices that should be active. If either the
     //     input or output list is not set, devices in that category are
     //     unaffected.
     //     </p>
     //     <p>It is an error to pass in a non-existent device ID.</p>
     //     <p><b>NOTE:</b> While the method signature allows device IDs to be
     //     passed as a list of strings, this method of setting active devices
     //     is deprecated and should not be relied upon to work. Please use
     //     $(ref: DeviceIdLists) instead.
@@ skipping 19 matching lines @@
     static void setMute(StreamType streamType,
                         boolean isMuted,
                         optional EmptyCallback callback);
   };
 
   interface Events {
     // Fired when anything changes to the audio device configuration.
     static void onDeviceChanged();
 
     // Fired when sound level changes for an active audio device.
-    // |id|: id of the audio device.
-    // |level|: new sound level of device(volume for output, gain for input).
-    static void OnLevelChanged(DOMString id, long level);
+    static void onLevelChanged(LevelChangedEvent event);
 
     // Fired when the mute state of the audio input or output changes.
     // Note that mute state is system-wide and the new value applies to every
     // audio device with specified stream type.
     static void onMuteChanged(MuteChangedEvent event);
 
     // Fired when audio devices change, either new devices being added, or
     // existing devices being removed.
     // |devices|: List of all present audio devices after the change.
-    static void OnDevicesChanged(AudioDeviceInfo[] devices);
+    static void onDeviceListChanged(AudioDeviceInfo[] devices);
   };
 };