Use mirror layer for minimized windows in overview mode

ash/common/wm/overview/window_grid.h

 // Copyright 2014 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_COMMON_WM_OVERVIEW_WINDOW_GRID_H_
 #define ASH_COMMON_WM_OVERVIEW_WINDOW_GRID_H_
 
 #include <stddef.h>
 
 #include <memory>
 #include <set>
 #include <vector>
 
 #include "ash/common/wm/overview/window_selector.h"
+#include "ash/common/wm/window_state_observer.h"
 #include "ash/common/wm_window_observer.h"
 #include "base/macros.h"
 #include "base/memory/scoped_vector.h"
 #include "base/scoped_observer.h"
 
 namespace views {
 class Widget;
 }
 
 namespace wm {
@@ skipping 14 matching lines @@
 // +-------+  +-------+  +-------+
 // |   3   |  |   4   |  |   5   |
 // +-------+  +-------+  +-------+
 // +-------+
 // |   6   |
 // +-------+
 // Example sequences:
 //  - Going right to left
 //    0, 1, 2, 3, 4, 5, 6
 //  - Going "top" to "bottom"
 //    0, 3, 6, 1, 4, 2, 5

[varkha, 2016/11/08 00:02:56]

Can you also please delete the 2 lines above this comment (or put a TODO(varkha)
to update the comment)? There is no vertical movement anymore.

[oshima, 2016/11/10 23:58:47]

Done.

 // The selector is switched to the next window grid (if available) or wrapped if
 // it reaches the end of its movement sequence.
-class ASH_EXPORT WindowGrid : public WmWindowObserver {
+class ASH_EXPORT WindowGrid : public WmWindowObserver,
+                              public wm::WindowStateObserver {
  public:
   WindowGrid(WmWindow* root_window,
              const std::vector<WmWindow*>& window_list,
              WindowSelector* window_selector);
   ~WindowGrid() override;
 
   // Exits overview mode, fading out the |shield_widget_| if necessary.
   void Shutdown();
 
   // Prepares the windows in this grid for overview. This will restore all
@@ skipping 53 matching lines @@
     return window_list_.get();
   }
 
   // WmWindowObserver:
   void OnWindowDestroying(WmWindow* window) override;
   // TODO(flackr): Handle window bounds changed in WindowSelectorItem.
   void OnWindowBoundsChanged(WmWindow* window,
                              const gfx::Rect& old_bounds,
                              const gfx::Rect& new_bounds) override;
 
+  // wm::WindowStateObserver:
+  void OnPostWindowStateTypeChange(wm::WindowState* window_state,
+                                   wm::WindowStateType old_type) override;
+
  private:
   friend class WindowSelectorTest;
 
   // Initializes the screen shield widget.
   void InitShieldWidget();
 
   // Internal function to initialize the selection widget.
   void InitSelectionWidget(WindowSelector::Direction direction);
 
   // Moves the selection widget to the specified |direction|.
@@ skipping 24 matching lines @@
   // Root window the grid is in.
   WmWindow* root_window_;
 
   // Pointer to the window selector that spawned this grid.
   WindowSelector* window_selector_;
 
   // Vector containing all the windows in this grid.
   ScopedVector<WindowSelectorItem> window_list_;
 
   ScopedObserver<WmWindow, WindowGrid> window_observer_;
+  ScopedObserver<wm::WindowState, WindowGrid> window_state_observer_;
 
   // Widget that darkens the screen background.
   std::unique_ptr<views::Widget> shield_widget_;
 
   // Widget that indicates to the user which is the selected window.
   std::unique_ptr<views::Widget> selection_widget_;
 
   // Shadow around the selector.
   std::unique_ptr<::wm::Shadow> selector_shadow_;
 
   // Current selected window position.
   size_t selected_index_;
 
   // Number of columns in the grid.
   size_t num_columns_;
 
   // True only after all windows have been prepared for overview.
   bool prepared_for_overview_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowGrid);
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_WM_OVERVIEW_WINDOW_GRID_H_