Implemented swipe to close in overview mode.

ash/wm/overview/transparent_activate_window_button.h

Index: ash/wm/overview/transparent_activate_window_button.h
diff --git a/ash/wm/overview/transparent_activate_window_button.h b/ash/wm/overview/transparent_activate_window_button.h
index c8c171a30abef0120f4210f215a282575ed5f751..76504abccec58d39f4f483c88221b8b5824c5dab 100644
--- a/ash/wm/overview/transparent_activate_window_button.h
+++ b/ash/wm/overview/transparent_activate_window_button.h
@@ -27,6 +27,10 @@ class TransparentActivateWindowButton : public views::ButtonListener {
   // Sets the bounds of the transparent window.
   void SetBounds(const gfx::Rect& bounds);
 
+  // Set the distance, in pixels, for which a drag gesture will cause a window
+  // to be closed when the drag distance exceeds |distance|.
+  void SetCloseWindowDistanceMinimum(int distance);
+
   // Sends an accessibility focus alert so that if chromevox is enabled, the
   // window title is read.
   void SendFocusAlert() const;