Revert "Metal rendering should account for cropping."

This reverts commit fc4a9c933326cac2eb048eb507e63021c75e705e.

Reason for revert: Remote video is not showing in a video call.

Original change's description:
> Metal rendering should account for cropping.
> 
> Also:
> - added a rotation override to allow ignoring frame rotation
> - fixed a couple of minor issues
> - made it possible to run the MTKView without the DisplayLink
> 
> Bug: webrtc:9301
> Change-Id: Ia83c152d9b6d45d56ceb80d287b5d3eacfaebddd
> Reviewed-on: https://webrtc-review.googlesource.com/78282
> Reviewed-by: Kári Helgason <kthelgason@webrtc.org>
> Reviewed-by: Anders Carlsson <andersc@webrtc.org>
> Commit-Queue: Peter Hanspers <peterhanspers@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#23452}

TBR=andersc@webrtc.org,kthelgason@webrtc.org,peterhanspers@webrtc.org

Change-Id: Iddf7793368531d2d7268c1ec138bb3a9874a4ab7
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: webrtc:9301
Reviewed-on: https://webrtc-review.googlesource.com/80020
Reviewed-by: JT Teh <jtteh@webrtc.org>
Commit-Queue: JT Teh <jtteh@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23455}

examples/objc/AppRTCMobile/ios/ARDVideoCallView.m

@@ -43,9 +43,7 @@ static CGFloat const kStatusBarHeight = 20;
   if (self = [super initWithFrame:frame]) {
 
 #if defined(RTC_SUPPORTS_METAL)
-    RTCMTLVideoView *metalView = [[RTCMTLVideoView alloc] initWithFrame:CGRectZero];
-    metalView.useDisplayLink = NO;
-    _remoteVideoView = metalView;
+    _remoteVideoView = [[RTCMTLVideoView alloc] initWithFrame:CGRectZero];
 #else
     RTCEAGLVideoView *remoteView = [[RTCEAGLVideoView alloc] initWithFrame:CGRectZero];
     remoteView.delegate = self;