add rotationOverride for RTCEAGLVideoView

Bug: webrtc:11221
Change-Id: I105b93de21fd2faeaf072c947c08006857c7a654
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/162460
Reviewed-by: Kári Helgason <kthelgason@webrtc.org>
Commit-Queue: Kári Helgason <kthelgason@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#30117}

sdk/objc/components/renderer/opengl/RTCEAGLVideoView.h

@@ -35,6 +35,9 @@ NS_EXTENSION_UNAVAILABLE_IOS("Rendering not available in app extensions.")
 - (instancetype)initWithCoder:(NSCoder *)aDecoder
                        shader:(id<RTCVideoViewShading>)shader NS_DESIGNATED_INITIALIZER;
 
+/** @abstract Wrapped RTCVideoRotation, or nil.
+ */
+@property(nonatomic, nullable) NSValue *rotationOverride;
 @end
 
 NS_ASSUME_NONNULL_END