Remove deprecated method from video decoder interface.

Bug: webrtc:9107
Change-Id: Ice022ff5887d27516eef38f9a0db7391c8acbaef
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/133905
Reviewed-by: Anders Carlsson <andersc@webrtc.org>
Commit-Queue: Kári Helgason <kthelgason@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#27732}
diff --git a/sdk/objc/base/RTCVideoDecoder.h b/sdk/objc/base/RTCVideoDecoder.h
index 18c6f6b..8077c69 100644
--- a/sdk/objc/base/RTCVideoDecoder.h
+++ b/sdk/objc/base/RTCVideoDecoder.h
@@ -26,9 +26,7 @@
 @protocol RTCVideoDecoder <NSObject>
 
 - (void)setCallback:(RTCVideoDecoderCallback)callback;
-- (NSInteger)startDecodeWithSettings:(RTCVideoEncoderSettings *)settings
-                       numberOfCores:(int)numberOfCores
-    DEPRECATED_MSG_ATTRIBUTE("use startDecodeWithNumberOfCores: instead");
+- (NSInteger)startDecodeWithNumberOfCores:(int)numberOfCores;
 - (NSInteger)releaseDecoder;
 - (NSInteger)decode:(RTCEncodedImage *)encodedImage
         missingFrames:(BOOL)missingFrames
@@ -36,10 +34,6 @@
          renderTimeMs:(int64_t)renderTimeMs;
 - (NSString *)implementationName;
 
-// TODO(andersc): Make non-optional when `startDecodeWithSettings:numberOfCores:` is removed.
-@optional
-- (NSInteger)startDecodeWithNumberOfCores:(int)numberOfCores;
-
 @end
 
 NS_ASSUME_NONNULL_END