Put iOS H264 High profile under a field trial

webrtc/sdk/objc/Framework/Classes/videotoolboxvideocodecfactory.h

 /*
  *  Copyright (c) 2016 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 10 matching lines @@
  public:
   VideoToolboxVideoEncoderFactory();
   ~VideoToolboxVideoEncoderFactory();
 
   // WebRtcVideoEncoderFactory implementation.
   VideoEncoder* CreateVideoEncoder(const cricket::VideoCodec& codec) override;
   void DestroyVideoEncoder(VideoEncoder* encoder) override;
   const std::vector<cricket::VideoCodec>& supported_codecs() const override;
 
  private:
-  std::vector<cricket::VideoCodec> supported_codecs_;
+  // TODO(magjed): Mutable because it depends on a field trial and it is
+  // recalculated every call to supported_codecs().
+  mutable std::vector<cricket::VideoCodec> supported_codecs_;
 };
 
 class VideoToolboxVideoDecoderFactory
     : public cricket::WebRtcVideoDecoderFactory {
  public:
   VideoToolboxVideoDecoderFactory();
   ~VideoToolboxVideoDecoderFactory();
 
   // WebRtcVideoDecoderFactory implementation.
   VideoDecoder* CreateVideoDecoder(VideoCodecType type) override;
   void DestroyVideoDecoder(VideoDecoder* decoder) override;
 
  private:
   std::vector<cricket::VideoCodec> supported_codecs_;
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_SDK_OBJC_FRAMEWORK_CLASSES_VIDEOTOOLBOXVIDEOCODECFACTORY_H_