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/api/video_codec/RTCWrappedNativeVideoDecoder.mm b/sdk/objc/api/video_codec/RTCWrappedNativeVideoDecoder.mm
index 6423c7a..dce479c 100644
--- a/sdk/objc/api/video_codec/RTCWrappedNativeVideoDecoder.mm
+++ b/sdk/objc/api/video_codec/RTCWrappedNativeVideoDecoder.mm
@@ -40,12 +40,6 @@
   return 0;
 }
 
-- (NSInteger)startDecodeWithSettings:(RTCVideoEncoderSettings *)settings
-                       numberOfCores:(int)numberOfCores {
-  RTC_NOTREACHED();
-  return 0;
-}
-
 - (NSInteger)releaseDecoder {
   RTC_NOTREACHED();
   return 0;
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
diff --git a/sdk/objc/components/video_codec/RTCVideoDecoderH264.mm b/sdk/objc/components/video_codec/RTCVideoDecoderH264.mm
index 69ccc90..c334280 100644
--- a/sdk/objc/components/video_codec/RTCVideoDecoderH264.mm
+++ b/sdk/objc/components/video_codec/RTCVideoDecoderH264.mm
@@ -96,11 +96,6 @@
   return WEBRTC_VIDEO_CODEC_OK;
 }
 
-- (NSInteger)startDecodeWithSettings:(RTCVideoEncoderSettings *)settings
-                       numberOfCores:(int)numberOfCores {
-  return WEBRTC_VIDEO_CODEC_OK;
-}
-
 - (NSInteger)decode:(RTCEncodedImage *)inputImage
         missingFrames:(BOOL)missingFrames
     codecSpecificInfo:(nullable id<RTCCodecSpecificInfo>)info
diff --git a/sdk/objc/native/src/objc_video_decoder_factory.mm b/sdk/objc/native/src/objc_video_decoder_factory.mm
index c79fb06..00fac0c 100644
--- a/sdk/objc/native/src/objc_video_decoder_factory.mm
+++ b/sdk/objc/native/src/objc_video_decoder_factory.mm
@@ -38,15 +38,7 @@
       : decoder_(decoder), implementation_name_([decoder implementationName].stdString) {}
 
   int32_t InitDecode(const VideoCodec *codec_settings, int32_t number_of_cores) override {
-    if ([decoder_ respondsToSelector:@selector(startDecodeWithNumberOfCores:)]) {
-      return [decoder_ startDecodeWithNumberOfCores:number_of_cores];
-    } else {
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Wdeprecated-declarations"
-      RTCVideoEncoderSettings *settings = [[RTCVideoEncoderSettings alloc] init];
-      return [decoder_ startDecodeWithSettings:settings numberOfCores:number_of_cores];
-#pragma clang diagnostic pop
-    }
+    return [decoder_ startDecodeWithNumberOfCores:number_of_cores];
   }
 
   int32_t Decode(const EncodedImage &input_image,