[gtk/wip/chergert/quartz4u] move flipped/opaque to subclass

[Christian Hergert <chergert src gnome org>]

commit 6384f3ee16e9ebc83f3e26e30bcc6291ae3eed98
Author: Christian Hergert <chergert redhat com>
Date:   Fri May 1 15:28:04 2020 -0700

    move flipped/opaque to subclass

 gdk/macos/GdkMacosBaseView.c  |  5 -----
 gdk/macos/GdkMacosCairoView.c | 10 ++++++++++
 2 files changed, 10 insertions(+), 5 deletions(-)
---
diff --git a/gdk/macos/GdkMacosBaseView.c b/gdk/macos/GdkMacosBaseView.c
index c9e9db5a3b..b05d9728c9 100644
--- a/gdk/macos/GdkMacosBaseView.c
+++ b/gdk/macos/GdkMacosBaseView.c
@@ -97,9 +97,4 @@
     [self updateTrackingRect];
 }
 
--(BOOL)isOpaque
-{
-  return NO;
-}
-
 @end
diff --git a/gdk/macos/GdkMacosCairoView.c b/gdk/macos/GdkMacosCairoView.c
index ffb47a924f..0d9f7a4bed 100644
--- a/gdk/macos/GdkMacosCairoView.c
+++ b/gdk/macos/GdkMacosCairoView.c
@@ -33,4 +33,14 @@
   [super dealloc];
 }
 
+-(BOOL)isOpaque
+{
+  return NO;
+}
+
+-(BOOL)isFlipped
+{
+  return YES;
+}
+
 @end