Delete deprecated decode:...fragmentationHeader:... objc method.

Next step after cl https://webrtc-review.googlesource.com/72442.

Bug: webrtc:6471
Change-Id: I2cbb8cef37dbb0762bf5ef57f68d690a21f341de
Reviewed-on: https://webrtc-review.googlesource.com/73820
Reviewed-by: Anders Carlsson <andersc@webrtc.org>
Reviewed-by: Kári Helgason <kthelgason@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23143}
diff --git a/sdk/objc/Framework/Headers/WebRTC/RTCVideoCodec.h b/sdk/objc/Framework/Headers/WebRTC/RTCVideoCodec.h
index 063963d..c0d464e 100644
--- a/sdk/objc/Framework/Headers/WebRTC/RTCVideoCodec.h
+++ b/sdk/objc/Framework/Headers/WebRTC/RTCVideoCodec.h
@@ -173,23 +173,14 @@
 - (NSInteger)releaseDecoder;
 - (NSInteger)decode:(RTCEncodedImage *)encodedImage
           missingFrames:(BOOL)missingFrames
-    fragmentationHeader:(RTCRtpFragmentationHeader *)fragmentationHeader
       codecSpecificInfo:(nullable id<RTCCodecSpecificInfo>)info
-           renderTimeMs:(int64_t)renderTimeMs
-    DEPRECATED_MSG_ATTRIBUTE("use decode:missingFrames:codecSpecificInfo:renderTimeMs: instead");
+           renderTimeMs:(int64_t)renderTimeMs;
 - (NSString *)implementationName;
 
 // TODO(andersc): Make non-optional when `startDecodeWithSettings:numberOfCores:` is removed.
 @optional
 - (NSInteger)startDecodeWithNumberOfCores:(int)numberOfCores;
 
-// TODO(andersc): Make non-optional when `decode:...fragmentationHeader:...` is removed.
-@optional
-- (NSInteger)decode:(RTCEncodedImage *)encodedImage
-        missingFrames:(BOOL)missingFrames
-    codecSpecificInfo:(nullable id<RTCCodecSpecificInfo>)info
-         renderTimeMs:(int64_t)renderTimeMs;
-
 @end
 
 NS_ASSUME_NONNULL_END