Fixing some of the issues found by clang static analyzer.

Bug: webrtc:8737
Change-Id: Ib436449c493336e7c35a72a96dc88cccdbb5bbaf
Reviewed-on: https://webrtc-review.googlesource.com/39200
Commit-Queue: Peter Hanspers <peterhanspers@webrtc.org>
Reviewed-by: Henrik Andreassson <henrika@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#21607}
diff --git a/sdk/objc/Framework/Classes/PeerConnection/RTCWrappedNativeVideoDecoder.mm b/sdk/objc/Framework/Classes/PeerConnection/RTCWrappedNativeVideoDecoder.mm
index 7d82c5b..7529ebf 100644
--- a/sdk/objc/Framework/Classes/PeerConnection/RTCWrappedNativeVideoDecoder.mm
+++ b/sdk/objc/Framework/Classes/PeerConnection/RTCWrappedNativeVideoDecoder.mm
@@ -49,7 +49,7 @@
 - (NSInteger)decode:(RTCEncodedImage *)encodedImage
           missingFrames:(BOOL)missingFrames
     fragmentationHeader:(RTCRtpFragmentationHeader *)fragmentationHeader
-      codecSpecificInfo:(__nullable id<RTCCodecSpecificInfo>)info
+      codecSpecificInfo:(nullable id<RTCCodecSpecificInfo>)info
            renderTimeMs:(int64_t)renderTimeMs {
   RTC_NOTREACHED();
   return 0;