Added arrow key navigation to Overview Mode

ash/wm/overview/window_overview.h

Index: ash/wm/overview/window_overview.h
diff --git a/ash/wm/overview/window_overview.h b/ash/wm/overview/window_overview.h
index 502e3d921e886dbc3e453750ac7948f3a5966cac..3fc6c8dab7f08961f48878e879638c0c1cfd1c62 100644
--- a/ash/wm/overview/window_overview.h
+++ b/ash/wm/overview/window_overview.h
@@ -5,6 +5,8 @@
 #ifndef ASH_WM_OVERVIEW_WINDOW_OVERVIEW_H_
 #define ASH_WM_OVERVIEW_WINDOW_OVERVIEW_H_
 
+#include <vector>
+
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/scoped_vector.h"
@@ -13,6 +15,7 @@
 #include "ui/events/event_handler.h"
 #include "ui/gfx/display_observer.h"
 #include "ui/gfx/rect.h"
+#include "ui/gfx/vector2d.h"
 
 namespace aura {
 class Window;
@@ -34,6 +37,22 @@ namespace ash {
 class WindowSelector;
 class WindowSelectorItem;
 
+// Represents a grid of windows in OM. Useful for arrow key navigation.

[tdanderson, 2014/04/29 14:46:27]

"OM" -> "Overview Mode"

[Nina, 2014/04/29 18:31:40]

Done.

+struct WindowGrid {
+  size_t rows;
+  size_t columns;
+  size_t windows;
+  aura::Window* root_window;
+  std::vector<std::vector<WindowSelectorItem*> > window_matrix;
+};
+
+// Represents the position of the cursor in the screen.
+struct ArrowCursor {
+  size_t x;
+  size_t y;
+  bool primary_display;
+};
+
 // The WindowOverview shows a grid of all of your windows and allows selecting
 // a window by clicking or tapping on it. It also displays a selection widget
 // used to indicate the current selection when alt-tabbing between windows.
@@ -51,7 +70,8 @@ class WindowOverview : public ui::EventHandler,
                  aura::Window* single_root_window);
   virtual ~WindowOverview();
 
-  // Sets the selected window to be the window in position |index|.
+  // Sets the selected window to be the window in position |index|, according to
+  // MRU order.
   void SetSelection(size_t index);
 
   // Dispatched when the list of windows has changed.
@@ -72,6 +92,18 @@ class WindowOverview : public ui::EventHandler,
   virtual void OnDisplayRemoved(const gfx::Display& display) OVERRIDE;
 
  private:
+  enum Direction {
+    DOWN,
+    UP,
+    RIGHT,
+    LEFT,
+    NONE
+  };

[tdanderson, 2014/04/29 14:46:27]

space

[Nina, 2014/04/29 18:31:40]

Done.

+  // Moves the selection widget to the specified window |target| fading out in
+  // the specified |fade_out_direction|.
+  void MoveSelectionWidget(WindowSelectorItem* target,
+                           gfx::Vector2d* fade_out_direction);
+
   // Returns the target of |event| or NULL if the event is not targeted at
   // any of the windows in the selector.
   aura::Window* GetEventTarget(ui::LocatedEvent* event);
@@ -93,10 +125,21 @@ class WindowOverview : public ui::EventHandler,
                              bool animate);
 
   // Creates the selection widget.
-  void InitializeSelectionWidget();
+  void InitializeSelectionWidget(aura::Window* root_window);
 
-  // Returns the bounds for the selection widget for the windows_ at |index|.
-  gfx::Rect GetSelectionBounds(size_t index);
+  // Moves the selection widget one step in a certain direction. Called when
+  // pressing an arrow key.
+  void MoveSelector(Direction direction);
+
+  // "Resets" the selection widget when recreating the overview after a window
+  // is closed, moving it to a new position.
+  void ResetSelectionWidget();
+
+  // Returns the bounds for the selection widget for the specified |window|

[tdanderson, 2014/04/29 14:46:27]

. at end

+  gfx::Rect GetSelectionBounds(WindowSelectorItem* window);
+
+  // Return a window by index, either by |mru| order or spatial order.
+  WindowSelectorItem* GetWindowByIndex(size_t index, bool mru);
 
   // Weak pointer to the window selector which owns this class.
   WindowSelector* window_selector_;
@@ -109,9 +152,9 @@ class WindowOverview : public ui::EventHandler,
   // Widget indicating which window is currently selected.
   scoped_ptr<views::Widget> selection_widget_;
 
-  // Index of the currently selected window. This is used to determine when the
-  // selection changes rows and use a different animation.
-  size_t selection_index_;
+  // Pointer to the currently selected window. This is used for the arrow key

[tdanderson, 2014/04/29 14:46:27]

Indicate in the comment that this is NULL if no window is currently selected.

+  // navigation.
+  ash::WindowSelectorItem* selected_window_;

[tdanderson, 2014/04/29 14:46:27]

ash:: not needed

 
   // If NULL, each root window displays an overview of the windows in that
   // display. Otherwise, all windows are in a single overview on
@@ -128,6 +171,15 @@ class WindowOverview : public ui::EventHandler,
   // overview.
   aura::WindowTracker hidden_windows_;
 
+  // Each grid represents the arrangement of windows in the screen while in
+  // overview mode.
+  WindowGrid main_grid_;
+  WindowGrid secondary_grid_;
+
+  // Used to store the location of the cursor used to select with the arrow
+  // keys.
+  ArrowCursor arrow_cursor_;

[tdanderson, 2014/04/29 14:46:27]

When I hear "arrow cursor" I think of an arrow-shaped mouse cursor, so for that
reason I don't like this name. I'd prefer if we used the term "selection widget"
consistently.

[Nina, 2014/04/29 18:31:40]

Done.

+
   DISALLOW_COPY_AND_ASSIGN(WindowOverview);
 };