ash: Add accelerator for snapping windows left/right.

ash/wm/workspace/snap_sizer.h

 // Copyright (c) 2012 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_WM_WORKSPACE_SNAP_SIZER_H_
 #define ASH_WM_WORKSPACE_SNAP_SIZER_H_
 #pragma once
 
 #include "ash/ash_export.h"
 #include "base/basictypes.h"
@@ skipping 20 matching lines @@
             const gfx::Point& start,
             Edge edge,
             int grid_size);
 
   // Updates the target bounds based on a mouse move.
   void Update(const gfx::Point& location);
 
   // Bounds to position the window at.
   const gfx::Rect& target_bounds() const { return target_bounds_; }
 
+  // Returns the appropriate snap bounds (e.g. if a window is already snapped,
+  // then it returns the next snap-bounds).
+  gfx::Rect GetSnapBounds(const gfx::Rect& bounds);
+
  private:
   // Calculates the amount to increment by. This returns one of -1, 0 or 1 and
   // is intended to by applied to |percent_index_|. |x| is the current
   // x-coordinate, and |reference_x| is used to determine whether to increase
   // or decrease the position. It's one of |last_adjust_x_| or |last_update_x_|.
   int CalculateIncrement(int x, int reference_x) const;
 
   // Changes the bounds. |x| is the current x-coordinate and |delta| the amount
   // to increase by. |delta| comes from CalculateIncrement() and is applied
   // to |percent_index_|.
   void ChangeBounds(int x, int delta);
 
   // Returns the target bounds based on the edge and |percent_index_|.
   gfx::Rect GetTargetBounds() const;
 
+  gfx::Rect GetTargetBoundsForPercent(int percent_index) const;
+
   // Returns true if the specified point is along the edge of the screen.
   bool AlongEdge(int x) const;
 
   // Window being snapped.
   aura::Window* window_;
 
   const Edge edge_;
   const int grid_size_;
 
   // Current target bounds for the snap.
@@ skipping 15 matching lines @@
   // X-coordinate last supplied to Update().
   int last_update_x_;
 
   DISALLOW_COPY_AND_ASSIGN(SnapSizer);
 };
 
 }  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_WM_WORKSPACE_SNAP_SIZER_H_