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

ash/common/wm/overview/window_selector_controller.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_CONTROLLER_H_
 #define ASH_COMMON_WM_OVERVIEW_WINDOW_SELECTOR_CONTROLLER_H_
 
 #include <list>
 #include <memory>
 #include <vector>
@@ skipping 19 matching lines @@
   // at certain times, such as when the lock screen is visible.
   static bool CanSelect();
 
   // Attempts to toggle overview mode and returns true if successful (showing
   // overview would be unsuccessful if there are no windows to show).
   bool ToggleOverview();
 
   // Returns true if window selection mode is active.
   bool IsSelecting() const;
 
+  // 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();
+
   // Returns true if overview mode is restoring minimized windows so that they
   // are visible during overview mode.
   bool IsRestoringMinimizedWindows() const;
 
   // WindowSelectorDelegate:
   void OnSelectionEnded() override;
   void AddDelayedAnimationObserver(
       std::unique_ptr<DelayedAnimationObserver> animation) override;
   void RemoveAndDestroyAnimationObserver(
       DelayedAnimationObserver* animation) override;
@@ skipping 11 matching lines @@
   std::vector<std::unique_ptr<DelayedAnimationObserver>> delayed_animations_;
   std::unique_ptr<WindowSelector> window_selector_;
   base::Time last_selection_time_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowSelectorController);
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_WM_OVERVIEW_WINDOW_SELECTOR_CONTROLLER_H_