Introduce PPB_AudioInput_Dev v0.3 and refactor the device enumeration code:

ppapi/api/dev/ppb_device_ref_dev.idl

 /* Copyright (c) 2012 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.
  */
 
 /**
  * This file defines the <code>PPB_DeviceRef_Dev</code> interface.
  */
 
 [generate_thunk]
 
 label Chrome {
   M18 = 0.1
 };
 
 /**
+ * Defines the callback type to receive device change notifications for
+ * <code>PPB_AudioInput_Dev.MonitorDeviceChange()</code> and
+ * <code>PPB_VideoCapture_Dev.MonitorDeviceChange()</code>.
+ *
+ * @param[inout] user_data The opaque pointer that the caller passed into
+ * <code>MonitorDeviceChange()</code>.
+ * @param[in] device_count How many devices in the array.
+ * @param[in] devices An array of <code>PPB_DeviceRef_Dev</code>. Please note
+ * that the ref count of the elements is not increased on behalf of the plugin.
+ */
+typedef void PP_MonitorDeviceChangeCallback(
+    [inout] mem_t user_data,
+    [in] uint32_t device_count,
+    [in, size_is(device_count)] PP_Resource[] devices);
+
+/**
  * Device types.
  */
 [assert_size(4)]
 enum PP_DeviceType_Dev {
   PP_DEVICETYPE_DEV_INVALID = 0,
   PP_DEVICETYPE_DEV_AUDIOCAPTURE = 1,
   PP_DEVICETYPE_DEV_VIDEOCAPTURE = 2
 };
 
 interface PPB_DeviceRef_Dev {
@@ skipping 24 matching lines @@
    *
    * @param[in] device_ref A <code>PP_Resource</code> corresponding to a device
    * reference.
    *
    * @return A <code>PP_Var</code> of type <code>PP_VARTYPE_STRING</code>
    * containing the name of the device if successful; a <code>PP_Var</code> of
    * type <code>PP_VARTYPE_UNDEFINED</code> if failed.
    */
   PP_Var GetName([in] PP_Resource device_ref);
 };