Fix rendering on an iPhone X's tall screen.

Bug: webrtc:8884
Change-Id: I850e4ea1919837e15a78c90968a4879a1ccbd22c
Reviewed-on: https://webrtc-review.googlesource.com/52761
Reviewed-by: Kári Helgason <kthelgason@webrtc.org>
Commit-Queue: Kári Helgason <kthelgason@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#22011}
diff --git a/sdk/objc/Framework/Classes/Metal/RTCMTLVideoView.m b/sdk/objc/Framework/Classes/Metal/RTCMTLVideoView.m
index 48c3f33..0e17777 100644
--- a/sdk/objc/Framework/Classes/Metal/RTCMTLVideoView.m
+++ b/sdk/objc/Framework/Classes/Metal/RTCMTLVideoView.m
@@ -90,7 +90,7 @@
   if (_metalView) {
     _metalView.delegate = self;
     [self addSubview:_metalView];
-    _metalView.contentMode = UIViewContentModeScaleAspectFit;
+    _metalView.contentMode = UIViewContentModeScaleAspectFill;
   }
 }