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 0fe374732cd1058ece4b6b1d4b27b38d73b48acb..0c4dfcc80236021d9a14750746f4f08d0e286ae4 100644
--- a/ash/wm/overview/transparent_activate_window_button.h
+++ b/ash/wm/overview/transparent_activate_window_button.h
@@ -20,7 +20,7 @@ class Widget;
 }  // namespace views
 
 namespace ash {
-
+class TransparentButton;
 class TransparentActivateWindowButtonDelegate;
 
 // Transparent window that covers window selector items and handles mouse and
@@ -38,6 +38,10 @@ class TransparentActivateWindowButton {
   // 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;
@@ -50,7 +54,7 @@ class TransparentActivateWindowButton {
   scoped_ptr<views::Widget> event_handler_widget_;
 
   // The transparent button view that handles user input. Not owned.
-  views::Button* transparent_button_;
+  TransparentButton* transparent_button_;
 
   DISALLOW_COPY_AND_ASSIGN(TransparentActivateWindowButton);
 };