Implemented swipe to close in overview mode.

ash/wm/overview/window_selector_item.h

Index: ash/wm/overview/window_selector_item.h
diff --git a/ash/wm/overview/window_selector_item.h b/ash/wm/overview/window_selector_item.h
index 584d2758929ac36442240948171031f7bb494e0e..6fa6b0dd1f1c780c95807105780d45d6aece16a3 100644
--- a/ash/wm/overview/window_selector_item.h
+++ b/ash/wm/overview/window_selector_item.h
@@ -18,12 +18,12 @@
 
 namespace aura {
 class Window;
-}
+}  // namespace aura
 
 namespace views {
 class Label;
 class Widget;
-}
+}  // namespace views
 
 namespace ash {
 
@@ -102,7 +102,10 @@ class ASH_EXPORT WindowSelectorItem
   void OnWindowTitleChanged(aura::Window* window) override;
 
   // ash::TransparentActivateWindowButtonDelegate:
+  void Scroll(int delta_x) override;
+  void CancelScroll() override;
   void Select() override;
+  void Close() override;
 
  private:
   friend class WindowSelectorTest;
@@ -128,6 +131,10 @@ class ASH_EXPORT WindowSelectorItem
   // Initializes window_label_.
   void CreateWindowLabel(const base::string16& title);
 
+  // Set the minimum distance, in pixels, for which a scroll gesture will cause
+  // a window to be closed when the scroll distance exceeds |distance|.
+  void SetCloseWindowDistanceMinimum(int distance);
+
   // Updates the bounds and accessibility names for all the transparent
   // overlays.
   void UpdateSelectorButtons();