Fixing invalid window opacity/visibility combination with the shelf

ash/shelf/shelf_layout_manager.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 "ash/shelf/shelf_layout_manager.h"
 
 #include <algorithm>
 #include <cmath>
 #include <cstring>
 #include <string>
@@ skipping 705 matching lines @@
   if (observer)
     status_animation_setter.AddObserver(observer);
 
   GetLayer(shelf_)->SetOpacity(target_bounds.opacity);
   shelf_->SetBounds(ScreenUtil::ConvertRectToScreen(
        shelf_->GetNativeView()->parent(),
        target_bounds.shelf_bounds_in_root));
 
   GetLayer(shelf_->status_area_widget())->SetOpacity(
       target_bounds.status_opacity);
+
+  // Having a window which is visible but does not have an opacity is an illegal
+  // state. We therefore show / hide the shelf here if required.
+  if (!target_bounds.status_opacity)
+    shelf_->status_area_widget()->Hide();
+  else if (target_bounds.status_opacity)
+    shelf_->status_area_widget()->Show();
+
   // TODO(harrym): Once status area widget is a child view of shelf
   // this can be simplified.
   gfx::Rect status_bounds = target_bounds.status_bounds_in_shelf;
   status_bounds.set_x(status_bounds.x() +
                       target_bounds.shelf_bounds_in_root.x());
   status_bounds.set_y(status_bounds.y() +
                       target_bounds.shelf_bounds_in_root.y());
   shelf_->status_area_widget()->SetBounds(
       ScreenUtil::ConvertRectToScreen(
           shelf_->status_area_widget()->GetNativeView()->parent(),
@@ skipping 457 matching lines @@
 
 void ShelfLayoutManager::SessionStateChanged(
     SessionStateDelegate::SessionState state) {
   TargetBounds target_bounds;
   CalculateTargetBounds(state_, &target_bounds);
   UpdateBoundsAndOpacity(target_bounds, true, NULL);
   UpdateVisibilityState();
 }
 
 }  // namespace ash