ObjC: Add implementationName for injectable codecs

webrtc/sdk/objc/Framework/Headers/WebRTC/RTCVideoCodec.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.
  */
 
@@ skipping 110 matching lines @@
 
 - (void)setCallback:(RTCVideoEncoderCallback)callback;
 - (NSInteger)startEncodeWithSettings:(RTCVideoEncoderSettings *)settings
                        numberOfCores:(int)numberOfCores;
 - (NSInteger)releaseEncoder;
 - (void)destroy;
 - (NSInteger)encode:(RTCVideoFrame *)frame
     codecSpecificInfo:(id<RTCCodecSpecificInfo>)info
            frameTypes:(NSArray<NSNumber *> *)frameTypes;
 - (BOOL)setBitrate:(uint32_t)bitrateKbit framerate:(uint32_t)framerate;
+- (NSString *)implementationName;
 
 /** Returns QP scaling settings for encoder. The quality scaler adjusts the resolution in order to
  *  keep the QP from the encoded images within the given range. Returning nil from this function
  *  disables quality scaling. */
 - (RTCVideoEncoderQpThresholds *)scalingSettings;
 
-// TODO(andersc): Add implementationName method.
-
 @end
 
 /** Protocol for decoder implementations. */
 RTC_EXPORT
 @protocol RTCVideoDecoder <NSObject>
 
 - (void)setCallback:(RTCVideoDecoderCallback)callback;
 - (NSInteger)startDecodeWithSettings:(RTCVideoEncoderSettings *)settings
                        numberOfCores:(int)numberOfCores;
 - (NSInteger)releaseDecoder;
 - (void)destroy;
 - (NSInteger)decode:(RTCEncodedImage *)encodedImage
           missingFrames:(BOOL)missingFrames
     fragmentationHeader:(RTCRtpFragmentationHeader *)fragmentationHeader
       codecSpecificInfo:(__nullable id<RTCCodecSpecificInfo>)info
            renderTimeMs:(int64_t)renderTimeMs;
-
-// TODO(andersc): Add implementationName method.
+- (NSString *)implementationName;
 
 @end
 
 NS_ASSUME_NONNULL_END