VideoCaptureDeviceFactory: Change device enumeration to callback + QTKit enumerates in UI thread.

media/video/capture/mac/video_capture_device_qtkit_mac.h

 // Copyright (c) 2011 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.
 
 // VideoCaptureDeviceQTKit implements all QTKit related code for
 // communicating with a QTKit capture device.
 
 #ifndef MEDIA_VIDEO_CAPTURE_MAC_VIDEO_CAPTURE_DEVICE_QTKIT_MAC_H_
 #define MEDIA_VIDEO_CAPTURE_MAC_VIDEO_CAPTURE_DEVICE_QTKIT_MAC_H_
 
@@ skipping 21 matching lines @@
   // QTKit variables.
   QTCaptureSession *captureSession_;
   QTCaptureDeviceInput *captureDeviceInput_;
 
   // Buffer for adjusting frames which do not fit receiver
   // assumptions.  scoped_array<> might make more sense, if the size
   // can be proven invariant.
   std::vector<UInt8> adjustedFrame_;
 }
 
-// Returns a dictionary of capture devices with friendly name and unique id.
+// Fills up the |deviceNames| dictionary of capture devices with friendly name
+// and unique id. No thread assumptions, but this method should run in UI
+// thread, see http://crbug.com/139164
++ (void)getDeviceNames:(NSMutableDictionary*)deviceNames;
+
+// Returns a dictionary of capture devices with friendly name and unique id, via
+// runing +getDeviceNames: on Main Thread.
 + (NSDictionary*)deviceNames;
 
 // Initializes the instance and registers the frame receiver.
 - (id)initWithFrameReceiver:(media::VideoCaptureDeviceMac*)frameReceiver;
 
 // Set the frame receiver.
 - (void)setFrameReceiver:(media::VideoCaptureDeviceMac*)frameReceiver;
 
 // Sets which capture device to use. Returns YES on sucess, NO otherwise.
 - (BOOL)setCaptureDevice:(NSString*)deviceId;
 
 // Configures the capture properties.
 - (BOOL)setCaptureHeight:(int)height width:(int)width frameRate:(int)frameRate;
 
 // Start video capturing. Returns YES on sucess, NO otherwise.
 - (BOOL)startCapture;
 
 // Stops video capturing.
 - (void)stopCapture;
 
 // Handle any QTCaptureSessionRuntimeErrorNotifications.
 - (void)handleNotification:(NSNotification*)errorNotification;
 
 @end
 
 #endif  // MEDIA_VIDEO_CAPTURE_MAC_VIDEO_CAPTURE_DEVICE_QTKIT_MAC_H_