Add method on AVFoundation capturer to adapt output format.

webrtc/sdk/objc/Framework/Classes/avfoundationvideocapturer.mm

 /*
  *  Copyright 2015 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 95 matching lines @@
 }
 
 void AVFoundationVideoCapturer::SetUseBackCamera(bool useBackCamera) {
   _capturer.useBackCamera = useBackCamera;
 }
 
 bool AVFoundationVideoCapturer::GetUseBackCamera() const {
   return _capturer.useBackCamera;
 }
 
+void AVFoundationVideoCapturer::AdaptOutputFormat(int width, int height, int fps) {
+  cricket::VideoFormat format(width, height, cricket::VideoFormat::FpsToInterval(fps), 0);
+  video_adapter()->OnOutputFormatRequest(format);
+}
+
 void AVFoundationVideoCapturer::CaptureSampleBuffer(
     CMSampleBufferRef sample_buffer, VideoRotation rotation) {
   if (CMSampleBufferGetNumSamples(sample_buffer) != 1 ||
       !CMSampleBufferIsValid(sample_buffer) ||
       !CMSampleBufferDataIsReady(sample_buffer)) {
     return;
   }
 
   CVImageBufferRef image_buffer = CMSampleBufferGetImageBuffer(sample_buffer);
   if (image_buffer == NULL) {
@@ skipping 44 matching lines @@
         buffer->width(), buffer->height(),
         static_cast<libyuv::RotationMode>(rotation));
     buffer = rotated_buffer;
   }
 
   OnFrame(webrtc::VideoFrame(buffer, rotation, translated_camera_time_us),
           captured_width, captured_height);
 }
 
 }  // namespace webrtc