Bug 1737831 - Also detect when the screen has a notch and, if so, don't shift by the menubar height either. r=mac-reviewers,mstange

This should fix the M1 mac case. Not sure if the SDKDeclarations bits is
in the right place, hopefully it is.

Differential Revision: https://phabricator.services.mozilla.com/D134632

widget/cocoa/SDKDeclarations.h

@@ -118,6 +118,11 @@ AXTextMarkerRef AXTextMarkerRangeCopyStartMarker(AXTextMarkerRangeRef text_marke
 AXTextMarkerRef AXTextMarkerRangeCopyEndMarker(AXTextMarkerRangeRef text_marker_range);
 }
 
+@interface NSScreen (NSScreen12_0)
+// https://developer.apple.com/documentation/appkit/nsscreen/3882821-safeareainsets?language=objc&changes=latest_major
+@property(readonly) NSEdgeInsets safeAreaInsets;
+@end
+
 #endif
 
 #endif  // SDKDefines_h

widget/cocoa/nsCocoaWindow.mm

@@ -3686,6 +3686,15 @@ static const NSString* kStateWantsTitleDrawn = @"wantsTitleDrawn";
   }
 }
 
+static bool ScreenHasNotch(nsCocoaWindow* aGeckoWindow) {
+  if (@available(macOS 12.0, *)) {
+    nsCOMPtr<nsIScreen> widgetScreen = aGeckoWindow->GetWidgetScreen();
+    NSScreen* cocoaScreen = ScreenHelperCocoa::CocoaScreenForScreen(widgetScreen);
+    return cocoaScreen.safeAreaInsets.top != 0.0f;
+  }
+  return false;
+}
+
 - (void)updateTitlebarShownAmount:(CGFloat)aShownAmount {
   NSInteger styleMask = [self styleMask];
   if (!(styleMask & NSWindowStyleMaskFullScreen)) {
@@ -3714,7 +3723,7 @@ static const NSString* kStateWantsTitleDrawn = @"wantsTitleDrawn";
       // [ToolbarWindow titlebarHeight]. titlebarHeight returns 0 when we're in
       // fullscreen.
       CGFloat shiftByPixels = mInitialTitlebarHeight * aShownAmount;
-      if (!gMenubarAlwaysShownInFullScreen) {
+      if (!gMenubarAlwaysShownInFullScreen && !ScreenHasNotch(geckoWindow)) {
         shiftByPixels += mMenuBarHeight * aShownAmount;
       }
       // Use mozilla::DesktopToLayoutDeviceScale rather than the