MacViews: Trigger shadow invalidation when a translucent window is shown.

ui/views/cocoa/bridged_native_widget.mm

Index: ui/views/cocoa/bridged_native_widget.mm
diff --git a/ui/views/cocoa/bridged_native_widget.mm b/ui/views/cocoa/bridged_native_widget.mm
index d4e0125716d49df204a2ff73a0446574c4832144..9e80b288a34da2531e5187b671add51741df2ce4 100644
--- a/ui/views/cocoa/bridged_native_widget.mm
+++ b/ui/views/cocoa/bridged_native_widget.mm
@@ -839,6 +839,11 @@ NSComparisonResult SubviewSorter(NSViewComparatorValue lhs,
   if (layer()) {
     layer()->SetVisible(window_visible_);
     layer()->SchedulePaint(gfx::Rect(GetClientAreaSize()));
+
+    // For translucent windows which are made visible, recalculate shadow when
+    // the frame from the compositor arrives.
+    if (![window_ isOpaque])
+      invalidate_shadow_on_frame_swap_ = window_visible_;
   }
 
   NotifyVisibilityChangeDown();