Adjusts dragging logic to be less likely to trigger false positive switch from snapping to docking

ash/wm/workspace/two_step_edge_cycler.h

 // Copyright 2014 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_TWO_STEP_EDGE_CYCLER_H_
 #define ASH_WM_WORKSPACE_TWO_STEP_EDGE_CYCLER_H_
 
 #include "ash/ash_export.h"
 #include "base/basictypes.h"
 #include "base/time/time.h"
 #include "ui/gfx/geometry/point.h"
 
 namespace ash {
 
 // TwoStepEdgeCycler is responsible for cycling between two modes when the mouse
 // is at the edge of the workspace. The cycler does not loop so it is impossible
 // to get back to the first mode once the second mode is reached.
 // TwoStepEdgeCycler should be destroyed once the mouse moves off the edge of
 // the workspace.
 class ASH_EXPORT TwoStepEdgeCycler {
  public:
-  explicit TwoStepEdgeCycler(const gfx::Point& start);
+  // The direction in which a mouse should travel to switch mode.
+  enum Direction { DIRECTION_LEFT, DIRECTION_RIGHT };
+
+  explicit TwoStepEdgeCycler(const gfx::Point& start, Direction direction);
   ~TwoStepEdgeCycler();
 
   // Update which mode should be used as a result of a mouse / touch move.
   // |location| is the location of the event.
   void OnMove(const gfx::Point& location);
 
   bool use_second_mode() const { return second_mode_; }
 
  private:
   // Whether the second mode should be used.
   bool second_mode_;
 
   // Time OnMove() was last invoked.
   base::TimeTicks time_last_move_;
 
   // The number of moves since the cycler was constructed.
   int num_moves_;
 
   // Initial x-coordinate.
   int start_x_;
 
+  // x-coordinate when paused.
+  int paused_x_;
+
+  // Whether the movement was paused.
+  bool paused_;
+
+  // Determines a preferred movement direction that we are watching.
+  Direction direction_;
+
   DISALLOW_COPY_AND_ASSIGN(TwoStepEdgeCycler);
 };
 
 }  // namespace ash
 
 #endif  // ASH_WM_WORKSPACE_TWO_STEP_EDGE_CYCLER_H_