Change webcamPrivate.set/get/reset to async APIs.

extensions/common/api/webcam_private.idl

 // 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.
 
 // Webcam Private API.
 namespace webcamPrivate {
   enum PanDirection { stop, right, left };
   enum TiltDirection { stop, up, down };
   enum Protocol { visca };
-
+  enum InquireType { pan, tilt, zoom };
+  
   dictionary ProtocolConfiguration {
     Protocol? protocol;
   };
 
   dictionary WebcamConfiguration {
     double? pan;
     PanDirection? panDirection;
     double? tilt;
     TiltDirection? tiltDirection;
     double? zoom;
   };
 
   callback WebcamIdCallback = void(DOMString webcamId);
-  callback WebcamConfigurationCallback =
-      void(WebcamConfiguration configuration);
+  callback WebcamConfigurationCallback = void(double value);
 
   interface Functions {
     // Open a serial port that controls a webcam.
     static void openSerialWebcam(DOMString path, ProtocolConfiguration protocol,
                                  WebcamIdCallback callback);
 
     // Close a serial port connection to a webcam.
     static void closeWebcam(DOMString webcamId);
 
-    static void get(DOMString webcamId, WebcamConfigurationCallback callback);
+    static void get(DOMString webcamId, InquireType type,

[Zachary Kuznia, 2015/08/19 20:49:44]

This API shouldn't change, unless there are performance implications or side
effects to requesting all state.

+                    WebcamConfigurationCallback callback);
     static void set(DOMString webcamId, WebcamConfiguration config);
     static void reset(DOMString webcamId, WebcamConfiguration config);
   };
 };