Added arrow key navigation to Overview Mode

ash/wm/overview/window_selector.h

Index: ash/wm/overview/window_selector.h
diff --git a/ash/wm/overview/window_selector.h b/ash/wm/overview/window_selector.h
index bfb0c143f9d2e81c53ae0457556db87c230bcfb2..f1d27bcbac326be57a8bc45759b67d2299fd1948 100644
--- a/ash/wm/overview/window_selector.h
+++ b/ash/wm/overview/window_selector.h
@@ -39,6 +39,7 @@ namespace ash {
 class WindowSelectorDelegate;
 class WindowSelectorItem;
 class WindowSelectorTest;
+class WindowGrid;
 
 // The WindowSelector shows a grid of all of your windows, allowing to select
 // one by clicking or tapping on it.
@@ -48,6 +49,13 @@ class ASH_EXPORT WindowSelector
       public aura::WindowObserver,
       public aura::client::ActivationChangeObserver {
  public:
+  enum Direction {
+    RIGHT,
+    DOWN,
+    LEFT,
+    UP
+  };
+
   typedef std::vector<aura::Window*> WindowList;
   typedef ScopedVector<WindowSelectorItem> WindowSelectorItemList;
 
@@ -93,10 +101,11 @@ class ASH_EXPORT WindowSelector
   // Begins positioning windows such that all windows are visible on the screen.
   void StartOverview();
 
-  // Position all of the windows based on the current selection mode.
+  // Position all of the windows in the overview.
   void PositionWindows(bool animate);
-  // Position all of the windows from |root_window| on |root_window|.
-  void PositionWindowsFromRoot(aura::Window* root_window, bool animate);
+
+  // Creates the WindowGrid objects and populates them with the current windows.
+  void CreateWindowGrids();
 
   // Resets the stored window from RemoveFocusAndSetRestoreWindow to NULL. If
   // Hide and track all hidden windows not in overview.
@@ -133,6 +142,9 @@ class ASH_EXPORT WindowSelector
   // used to prevent handling the resulting expected activation.
   bool ignore_activations_;
 
+  // List of all the window overview grids, one for each window.

[tdanderson, 2014/05/28 16:01:19]

One for each root window?

[Nina, 2014/05/29 17:12:24]

Yes. Modified comment.

+  ScopedVector<WindowGrid> grid_list_;
+
   // The cursor client used to lock the current cursor during overview.
   aura::client::CursorClient* cursor_client_;
 
@@ -143,6 +155,9 @@ class ASH_EXPORT WindowSelector
   // overview.
   aura::WindowTracker hidden_windows_;
 
+  // Tracks the index of the root window the selection widget is in.
+  size_t root_index_;
+
   DISALLOW_COPY_AND_ASSIGN(WindowSelector);
 };