Add panels as a single group of windows per display for overview window cycling.

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 684 matching lines @@
   layer_->SetBounds(actual_new_bounds);
 
   // If we are currently not the layer's delegate, we will not get bounds
   // changed notification from the layer (this typically happens after animating
   // hidden). We must notify ourselves.
   if (layer_->delegate() != this)
     OnLayerBoundsChanged(old_bounds, ContainsMouse());
 }
 
 void Window::SetVisible(bool visible) {
-  if (visible == layer_->GetTargetVisibility())
+  if (visible == layer_->GetTargetVisibility()) {
+    // After calling SetVisible, IsVisible should immediately return the target
+    // visibility state.

[sky, 2013/09/13 21:46:44]

I think this is wrong. The reason you're seeing the behavior you are is you're
changing the visibility at the layer level directly. You need to go through
window otherwise things get out of sync.

[flackr, 2013/09/13 22:28:38]

I should provide some context. PanelLayoutManager::MinimizePanel it calls
Window::Hide and then in PanelLayoutManager::Relayout expects Window::IsVisible
to return false. Both of these calls are made on the Window and I think should
return a consistent result even though the layer is animating as described in
the comment in Window::IsVisible, but let me know what you think.

[sky, 2013/09/16 17:03:35]

725 updates visibility, so how come PanelLayoutManager is not seeing the correct
visible state?

+    visible_ = visible;
     return;  // No change.
+  }
 
   FOR_EACH_OBSERVER(WindowObserver, observers_,
                     OnWindowVisibilityChanging(this, visible));
 
   RootWindow* root_window = GetRootWindow();
   if (root_window)
     root_window->DispatchMouseExitToHidingWindow(this);
 
   client::VisibilityClient* visibility_client =
       client::GetVisibilityClient(this);
@@ skipping 376 matching lines @@
   bool contains_mouse = false;
   if (IsVisible()) {
     RootWindow* root_window = GetRootWindow();
     contains_mouse = root_window &&
         ContainsPointInRoot(root_window->GetLastMouseLocationInRoot());
   }
   return contains_mouse;
 }
 
 }  // namespace aura