GPU: Further improve vsync handling

src/util/platform_misc_mac.mm

@@ -147,3 +147,24 @@ void CocoaTools::DestroyMetalLayer(WindowInfo* wi)
   [view setWantsLayer:NO];
   [layer release];
 }
+
+std::optional<float> CocoaTools::GetViewRefreshRate(const WindowInfo& wi)
+{
+  if (![NSThread isMainThread])
+  {
+    std::optional<float> ret;
+    dispatch_sync(dispatch_get_main_queue(), [&ret, wi]{ ret = GetViewRefreshRate(wi); });
+    return ret;
+  }
+
+  std::optional<float> ret;
+  NSView* const view = (__bridge NSView*)wi.window_handle;
+  const u32 did = [[[[[view window] screen] deviceDescription] valueForKey:@"NSScreenNumber"] unsignedIntValue];
+  if (CGDisplayModeRef mode = CGDisplayCopyDisplayMode(did))
+  {
+    ret = CGDisplayModeGetRefreshRate(mode);
+    CGDisplayModeRelease(mode);
+  }
+
+  return ret;
+}