Removing RTC_SUPPORTS_METAL compilation flag. This flag is a holdover from before either macOS or the iOS Simulator supported Metal rendering.

Bug: webrtc:12638
Change-Id: I21054bdcf4c941086234562c4ee1740754050590
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/216700
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Kári Helgason <kthelgason@webrtc.org>
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34362}

examples/objc/AppRTCMobile/ios/ARDVideoCallView.m

@@ -12,10 +12,7 @@
 
 #import <AVFoundation/AVFoundation.h>
 
-#import "sdk/objc/components/renderer/opengl/RTCEAGLVideoView.h"
-#if defined(RTC_SUPPORTS_METAL)
-#import "sdk/objc/components/renderer/metal/RTCMTLVideoView.h"  // nogncheck
-#endif
+#import "sdk/objc/components/renderer/metal/RTCMTLVideoView.h"
 
 #import "UIImage+ARDUtilities.h"
 
@@ -44,14 +41,7 @@ static CGFloat const kStatusBarHeight = 20;
 - (instancetype)initWithFrame:(CGRect)frame {
   if (self = [super initWithFrame:frame]) {
 
-#if defined(RTC_SUPPORTS_METAL)
     _remoteVideoView = [[RTC_OBJC_TYPE(RTCMTLVideoView) alloc] initWithFrame:CGRectZero];
-#else
-    RTC_OBJC_TYPE(RTCEAGLVideoView) *remoteView =
-        [[RTC_OBJC_TYPE(RTCEAGLVideoView) alloc] initWithFrame:CGRectZero];
-    remoteView.delegate = self;
-    _remoteVideoView = remoteView;
-#endif
 
     [self addSubview:_remoteVideoView];