[Mac] Enumerate webcam devices on the main thread.

media/video/capture/mac/video_capture_device_qtkit_mac.mm

 // 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.
 
 #import "media/video/capture/mac/video_capture_device_qtkit_mac.h"
 
 #import <QTKit/QTKit.h>
 
 #include "base/logging.h"
 #include "media/video/capture/mac/video_capture_device_mac.h"
 #include "media/video/capture/video_capture_device.h"
 #include "media/video/capture/video_capture_types.h"
 
 @implementation VideoCaptureDeviceQTKit
 
 #pragma mark Class methods
 
-+ (NSDictionary *)deviceNames {
++ (void)getDeviceNames:(NSMutableDictionary*)deviceNames {
   NSArray *captureDevices =
       [QTCaptureDevice inputDevicesWithMediaType:QTMediaTypeVideo];
+
+  for (QTCaptureDevice* device in captureDevices) {
+    [deviceNames setObject:[device localizedDisplayName]
+                    forKey:[device uniqueID]];
+  }
+}
+
++ (NSDictionary *)deviceNames {

[sail, 2012/10/09 23:53:39]

no space before *

   NSMutableDictionary *deviceNames =
       [[[NSMutableDictionary alloc] init] autorelease];
 
-  for (QTCaptureDevice* device in captureDevices) {
-    NSString* qtDeviceName = [device localizedDisplayName];
-    NSString* qtUniqueId = [device uniqueID];
-    [deviceNames setObject:qtDeviceName forKey:qtUniqueId];
-  }
+  // TODO(shess): Post to the main thread to see if that helps
+  // http://crbug.com/139164
+  [self performSelectorOnMainThread:@selector(getDeviceNames:)
+                         withObject:deviceNames
+                      waitUntilDone:YES];
   return deviceNames;
 }
 
 #pragma mark Public methods
 
 - (id)initWithFrameReceiver:(media::VideoCaptureDeviceMac *)frameReceiver {
   self = [super init];
   if (self) {
     frameReceiver_ = frameReceiver;
     lock_ = [[NSLock alloc] init];
@@ skipping 181 matching lines @@
 
     // Deliver the captured video frame.
     frameReceiver_->ReceiveFrame(addressToPass, frameSize, captureCapability);
 
     CVPixelBufferUnlockBaseAddress(videoFrame, kLockFlags);
   }
   [lock_ unlock];
 }
 
 @end