ash: Fix transparency glitches in window header

ash/wm/frame_painter.h

 // 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.
 
 #ifndef ASH_WM_FRAME_PAINTER_H_
 #define ASH_WM_FRAME_PAINTER_H_
 #pragma once
 
 #include <set>
 
@@ skipping 92 matching lines @@
                      const gfx::Font& title_font);
 
   // Performs layout for the header based on whether we want the shorter
   // |maximized_layout| appearance.
   void LayoutHeader(views::NonClientFrameView* view, bool maximized_layout);
 
   // aura::WindowObserver overrides:
   virtual void OnWindowPropertyChanged(aura::Window* window,
                                        const void* key,
                                        intptr_t old) OVERRIDE;
+  virtual void OnWindowVisibilityChanged(aura::Window* window,
+                                         bool visible) OVERRIDE;
   virtual void OnWindowDestroying(aura::Window* window) OVERRIDE;
 
   // Overridden from ui::AnimationDelegate
   virtual void AnimationProgressed(const ui::Animation* animation) OVERRIDE;
 
  private:
   FRIEND_TEST_ALL_PREFIXES(FramePainterTest, Basics);
   FRIEND_TEST_ALL_PREFIXES(FramePainterTest, UseSoloWindowHeader);
 
   // Sets the images for a button base on IDs from the |frame_| theme provider.
   void SetButtonImages(views::ImageButton* button,
                        int normal_bitmap_id,
                        int hot_bitmap_id,
                        int pushed_bitmap_id);
 
   // Returns the offset between window left edge and title string.
   int GetTitleOffsetX() const;
 
   // Returns true if there is exactly one visible, normal-type window using
   // a header painted by this class, in which case we should paint a transparent
   // window header.
   static bool UseSoloWindowHeader();
 
+  // Schedules a paint for the window header of the solo window.  Invoke this
+  // when another window is hidden or destroyed to force the transparency of
+  // the now-solo window to update.
+  static void SchedulePaintForSoloWindow();
+
   static std::set<FramePainter*>* instances_;
 
   // Not owned
   views::Widget* frame_;
   views::View* window_icon_;  // May be NULL.
   views::ImageButton* size_button_;
   views::ImageButton* close_button_;
   aura::Window* window_;
 
   // Window frame header/caption parts.
@@ skipping 16 matching lines @@
   scoped_ptr<ui::SlideAnimation> crossfade_animation_;
 
   SizeButtonBehavior size_button_behavior_;
 
   DISALLOW_COPY_AND_ASSIGN(FramePainter);
 };
 
 }  // namespace ash
 
 #endif  // ASH_WM_FRAME_PAINTER_H_