Fixing invalid window opacity/visibility combination with the shelf

ui/aura/window.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/aura/window.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 320 matching lines @@
   const Window* root_window = GetRootWindow();
   return root_window ? root_window->host_ : NULL;
 }
 
 void Window::Show() {
   if (layer()) {
     DCHECK_EQ(visible_, layer()->GetTargetVisibility());
     // 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));

[sky, 2014/05/13 21:43:07]

I think you should land this separately. That way if you have to revert you're
only reverting this part of the change.

[Mr4D (OOO till 08-26), 2014/05/13 22:08:17]

Indeed! Thanks, good idea! Done.

   }
   SetVisible(true);
 }
 
 void Window::Hide() {
   // RootWindow::OnVisibilityChanged will call ReleaseCapture.
   SetVisible(false);
 }
 
 bool Window::IsVisible() const {
@@ skipping 1074 matching lines @@
       return window;
     if (offset)
       *offset += window->bounds().OffsetFromOrigin();
   }
   if (offset)
     *offset = gfx::Vector2d();
   return NULL;
 }
 
 }  // namespace aura