Fix low frame rate problems in high resolution USB cameras using AVFoundation

media/capture/video/mac/video_capture_device_avfoundation_mac.mm

Index: media/capture/video/mac/video_capture_device_avfoundation_mac.mm
diff --git a/media/capture/video/mac/video_capture_device_avfoundation_mac.mm b/media/capture/video/mac/video_capture_device_avfoundation_mac.mm
index 0145616d7d933c8a0311df4722e940df5a34728b..10a079225ac95c4e5af4a1b9dd7a15f0f83f8939 100644
--- a/media/capture/video/mac/video_capture_device_avfoundation_mac.mm
+++ b/media/capture/video/mac/video_capture_device_avfoundation_mac.mm
@@ -261,6 +261,12 @@ void ExtractBaseAddressAndLength(char** base_address,
   }
   [captureSession_ addInput:captureDeviceInput_];
 
+  // Create and plug the still image capture output. This should happen in
+  // advance of the actual picture to allow for the 3A to stabilize.
+  stillImageOutput_.reset([[AVCaptureStillImageOutput alloc] init]);
+  if (stillImageOutput_ && [captureSession_ canAddOutput:stillImageOutput_])
+    [captureSession_ addOutput:stillImageOutput_];
+
   // Create a new data output for video. The data output is configured to
   // discard late frames by default.
   captureVideoDataOutput_.reset([[AVCaptureVideoDataOutput alloc] init]);
@@ -277,12 +283,6 @@ void ExtractBaseAddressAndLength(char** base_address,
                                   DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)];
   [captureSession_ addOutput:captureVideoDataOutput_];
 
-  // Create and plug the still image capture output. This should happen in
-  // advance of the actual picture to allow for the 3A to stabilize.
-  stillImageOutput_.reset([[AVCaptureStillImageOutput alloc] init]);
-  if (stillImageOutput_ && [captureSession_ canAddOutput:stillImageOutput_])
-    [captureSession_ addOutput:stillImageOutput_];
-
   return YES;
 }