[ash-md] Adds support for gesture to move selection in overview mode

ash/common/wm/overview/window_selector.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef ASH_COMMON_WM_OVERVIEW_WINDOW_SELECTOR_H_
 #define ASH_COMMON_WM_OVERVIEW_WINDOW_SELECTOR_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 43 matching lines @@
 
   // Perform cleanup that cannot be done in the destructor.
   void Shutdown();
 
   // Cancels window selection.
   void CancelSelection();
 
   // Called when the last window selector item from a grid is deleted.
   void OnGridEmpty(WindowGrid* grid);
 
+  // Moves the current selection by |increment| items. Positive values of
+  // |increment| move the selection forward, negative values move it backward.
+  void IncrementSelection(int increment);
+
+  // Accepts current selection if any. Returns true if a selection was made,
+  // false otherwise.
+  bool AcceptSelection();
+
   // Activates |item's| window.
   void SelectWindow(WindowSelectorItem* item);
 
   // Called when |window| is about to get closed.
   void WindowClosing(WindowSelectorItem* window);
 
   WindowSelectorDelegate* delegate() { return delegate_; }
 
   bool restoring_minimized_windows() const {
     return restoring_minimized_windows_;
@@ skipping 110 matching lines @@
   int text_filter_bottom_;
 
   bool is_shut_down_ = false;
 
   DISALLOW_COPY_AND_ASSIGN(WindowSelector);
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_WM_OVERVIEW_WINDOW_SELECTOR_H_