Not submitted - Fixing invalid visibility states with layers which showed up in unittests ...

ui/aura/window.cc

Index: ui/aura/window.cc
diff --git a/ui/aura/window.cc b/ui/aura/window.cc
index c55651b95c0f71642ecd8166c1e7b2fa39e5b3eb..ba0f8a41595cabf43e86c9e37f97fb419dd37462 100644
--- a/ui/aura/window.cc
+++ b/ui/aura/window.cc
@@ -360,8 +360,7 @@ void Window::Show() {
     // It is not allowed that a window is visible but the layers alpha is fully
     // transparent since the window would still be considered to be active but
     // could not be seen.
-    // TODO(skuhne): uncomment and fix issue 351553.
-    // DCHECK(!(visible_ && layer()->GetTargetOpacity() == 0.0f));
+    DCHECK(!(visible_ && layer()->GetTargetOpacity() == 0.0f));
   }
   SetVisible(true);
 }