Use overview mode for alt-tab cycling.

ash/wm/window_selector.h

Index: ash/wm/window_selector.h
diff --git a/ash/wm/window_selector.h b/ash/wm/window_selector.h
index 900787db4054262b3cb937a08270b3772c5fd444..92ed607eabc029d671b1ab5384a128e77978de2a 100644
--- a/ash/wm/window_selector.h
+++ b/ash/wm/window_selector.h
@@ -8,6 +8,8 @@
 #include <vector>
 
 #include "base/compiler_specific.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/scoped_vector.h"
 #include "ui/aura/window_observer.h"
 #include "ui/base/events/event_handler.h"
 #include "ui/gfx/transform.h"
@@ -16,21 +18,49 @@ namespace aura {
 class RootWindow;
 }
 
+namespace ui {
+class LocatedEvent;
+}
+
+namespace views {
+class Widget;
+}
+
 namespace ash {
 
 class WindowSelectorDelegate;
+class WindowSelectorWindow;
 
 // The WindowSelector shows a grid of all of your windows and allows selecting
-// a window by clicking or tapping on it.
+// a window by clicking or tapping on it (OVERVIEW mode) or by alt-tabbing to
+// it (CYCLE mode).
 class WindowSelector : public ui::EventHandler,
                        public aura::WindowObserver {
  public:
+  enum Direction {
+    FORWARD,
+    BACKWARD
+  };
+  enum Mode {
+    CYCLE,
+    OVERVIEW
+  };
+
   typedef std::vector<aura::Window*> WindowList;
 
   WindowSelector(const WindowList& windows,
+                 Mode mode,
                  WindowSelectorDelegate* delegate);
   virtual ~WindowSelector();
 
+  // Step to the next window in |direction|.
+  void Step(Direction direction);
+
+  // Select the current window.
+  void SelectWindow();
+
+  Mode mode() { return mode_; }
+
   // ui::EventHandler:
   virtual void OnEvent(ui::Event* event) OVERRIDE;
   virtual void OnMouseEvent(ui::MouseEvent* event) OVERRIDE;
@@ -40,37 +70,48 @@ class WindowSelector : public ui::EventHandler,
   virtual void OnWindowDestroyed(aura::Window* window) OVERRIDE;
 
  private:
-  struct WindowDetails {
-    WindowDetails() : window(NULL), minimized(false) {}
-
-    bool operator==(const aura::Window* other_window) const {
-      return window == other_window;
-    }
+  // Returns the target of |event| or NULL if the event is not targeted at
+  // any of the windows in the selector.
+  WindowSelectorWindow* GetEventTarget(ui::LocatedEvent* event);
 
-    // A weak pointer to the window.
-    aura::Window* window;
+  // Handles a selection event for |target|.
+  void HandleSelectionEvent(WindowSelectorWindow* target);
 
-    // If true, the window was minimized and this should be restored if the
-    // window was not selected.
-    bool minimized;
+  // Position all of the windows based on the current selection mode.
+  void PositionWindows();
+  // Position all of the windows from |root_window| on |root_window|.
+  void PositionWindowsFromRoot(aura::RootWindow* root_window);
+  // Position all of the |windows| to fit on the |root_window|.
+  void PositionWindowsOnRoot(aura::RootWindow* root_window,
+                             const std::vector<WindowSelectorWindow*>& windows);
 
-    // The original transform of the window before entering overview mode.
-    gfx::Transform original_transform;
-  };
+  void InitializeSelectionWidget();
 
-  void HandleSelectionEvent(ui::Event* event);
-  void PositionWindows();
-  void PositionWindowsOnRoot(aura::RootWindow* root_window);
+  // Updates the selection widget's location to the currently selected window.
+  // If |animate| the transition to the new location is animated.
+  void UpdateSelectionLocation(bool animate);
 
-  void SelectWindow(aura::Window*);
+  // The collection of windows in the overview wrapped by a helper class which
+  // restores their state and helps transform them to other root windows.
+  ScopedVector<WindowSelectorWindow> windows_;
 
-  // List of weak pointers of windows to select from.
-  std::vector<WindowDetails> windows_;
+  // The window selection mode.
+  Mode mode_;
 
   // Weak pointer to the selector delegate which will be called when a
   // selection is made.
   WindowSelectorDelegate* delegate_;
 
+  // Index of the currently selected window if the mode is CYCLE.
+  size_t selected_window_;
+
+  // Widget indicating which window is currently selected.
+  scoped_ptr<views::Widget> selection_widget_;
+
+  // In CYCLE mode, the root window in which selection is taking place.
+  // NULL otherwise.
+  aura::RootWindow* selection_root_;
+
   DISALLOW_COPY_AND_ASSIGN(WindowSelector);
 };