Reland of Injectable Obj-C video codecs

webrtc/sdk/objc/Framework/Classes/VideoToolbox/objc_video_encoder_factory.h

+/*
+ *  Copyright 2017 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.
+ */
+
+#ifndef WEBRTC_SDK_OBJC_FRAMEWORK_CLASSES_PEERCONNECTION_OBJC_VIDEO_ENCODER_FACTORY_H_
+#define WEBRTC_SDK_OBJC_FRAMEWORK_CLASSES_PEERCONNECTION_OBJC_VIDEO_ENCODER_FACTORY_H_
+
+#import <Foundation/Foundation.h>
+
+#include "webrtc/media/engine/webrtcvideoencoderfactory.h"
+
+@protocol RTCVideoEncoderFactory;
+
+namespace webrtc {
+
+class ObjCVideoEncoderFactory : public cricket::WebRtcVideoEncoderFactory {
+ public:
+  explicit ObjCVideoEncoderFactory(id<RTCVideoEncoderFactory>);
+  ~ObjCVideoEncoderFactory();
+
+  id<RTCVideoEncoderFactory> wrapped_encoder_factory() const;
+
+  webrtc::VideoEncoder* CreateVideoEncoder(
+      const cricket::VideoCodec& codec) override;
+  const std::vector<cricket::VideoCodec>& supported_codecs() const override;
+  void DestroyVideoEncoder(webrtc::VideoEncoder* encoder) override;
+
+ private:
+  id<RTCVideoEncoderFactory> encoder_factory_;
+  mutable std::vector<cricket::VideoCodec> supported_codecs_;
+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_SDK_OBJC_FRAMEWORK_CLASSES_PEERCONNECTION_OBJC_VIDEO_ENCODER_FACTORY_H_