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      1 // Copyright 2013 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef ASH_WM_MRU_WINDOW_TRACKER_H_
      6 #define ASH_WM_MRU_WINDOW_TRACKER_H_
      7 
      8 #include <list>
      9 #include <vector>
     10 
     11 #include "ash/ash_export.h"
     12 #include "base/basictypes.h"
     13 #include "base/memory/scoped_ptr.h"
     14 #include "ui/aura/window_observer.h"
     15 #include "ui/wm/public/activation_change_observer.h"
     16 
     17 namespace aura {
     18 class RootWindow;
     19 class Window;
     20 namespace client {
     21 class ActivationClient;
     22 }
     23 }
     24 
     25 namespace ash {
     26 
     27 // Maintains a most recently used list of windows. This is used for window
     28 // cycling using Alt+Tab and overview mode.
     29 class ASH_EXPORT MruWindowTracker
     30     : public aura::client::ActivationChangeObserver,
     31       public aura::WindowObserver {
     32  public:
     33   typedef std::vector<aura::Window*> WindowList;
     34 
     35   explicit MruWindowTracker(
     36       aura::client::ActivationClient* activation_client);
     37   virtual ~MruWindowTracker();
     38 
     39   // Returns the set of windows which can be cycled through. This method creates
     40   // the vector based on the current set of windows across all valid root
     41   // windows. As a result it is not necessarily the same as the set of
     42   // windows being iterated over.
     43   // If |top_most_at_end| the window list will return in ascending (lowest
     44   // window in stacking order first) order instead of the default descending
     45   // (top most window first) order.
     46   static WindowList BuildWindowList(bool top_most_at_end);
     47 
     48   // Returns the set of windows which can be cycled through using the tracked
     49   // list of most recently used windows.
     50   WindowList BuildMruWindowList();
     51 
     52   // Starts or stops ignoring window activations. If no longer ignoring
     53   // activations the currently active window is moved to the front of the
     54   // MRU window list. Used by WindowCycleList to avoid adding all cycled
     55   // windows to the front of the MRU window list.
     56   void SetIgnoreActivations(bool ignore);
     57 
     58  private:
     59   // Updates the mru_windows_ list to insert/move |active_window| at/to the
     60   // front.
     61   void SetActiveWindow(aura::Window* active_window);
     62 
     63   // Overridden from aura::client::ActivationChangeObserver:
     64   virtual void OnWindowActivated(aura::Window* gained_active,
     65                                  aura::Window* lost_active) OVERRIDE;
     66 
     67   // Overridden from WindowObserver:
     68   virtual void OnWindowDestroyed(aura::Window* window) OVERRIDE;
     69 
     70   // List of windows that have been activated in containers that we cycle
     71   // through, sorted by most recently used.
     72   std::list<aura::Window*> mru_windows_;
     73 
     74   aura::client::ActivationClient* activation_client_;
     75 
     76   bool ignore_window_activations_;
     77 
     78   DISALLOW_COPY_AND_ASSIGN(MruWindowTracker);
     79 };
     80 
     81 }  // namespace ash
     82 
     83 #endif  // ASH_WM_MRU_WINDOW_TRACKER_H_
     84