ObjC: Add support for injectable native audio and video codecs

webrtc/sdk/objc/Framework/Classes/PeerConnection/RTCPeerConnectionFactory+Native.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.
+ */
+
+#import "WebRTC/RTCPeerConnectionFactory.h"
+
+#include "webrtc/rtc_base/scoped_ref_ptr.h"
+
+namespace webrtc {
+
+class AudioEncoderFactory;
+class AudioDecoderFactory;
+
+}  // namespace webrtc
+
+namespace cricket {
+
+class WebRtcVideoEncoderFactory;
+class WebRtcVideoDecoderFactory;
+
+}  // namespace cricket
+
+NS_ASSUME_NONNULL_BEGIN
+
+/**
+ * This class extension exposes methods that work directly with injectable C++ components.
+ */
+@interface RTCPeerConnectionFactory ()
+
+/* Initialize object with injectable native audio/video encoder/decoder factories */
+- (instancetype)initWithNativeAudioEncoderFactory:
+                    (rtc::scoped_refptr<webrtc::AudioEncoderFactory>)audioEncoderFactory
+                        nativeAudioDecoderFactory:
+                            (rtc::scoped_refptr<webrtc::AudioDecoderFactory>)audioDecoderFactory
+                        nativeVideoEncoderFactory:
+                            (nullable cricket::WebRtcVideoEncoderFactory *)videoEncoderFactory
+                        nativeVideoDecoderFactory:
+                            (nullable cricket::WebRtcVideoDecoderFactory *)videoDecoderFactory
+    NS_DESIGNATED_INITIALIZER;
+
+@end
+
+NS_ASSUME_NONNULL_END