Postpone rail application for touch scrolling - chrome side.

ui/events/gesture_detection/snap_scroll_controller.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 UI_EVENTS_GESTURE_DETECTION_SNAP_SCROLL_CONTROLLER_H_
 #define UI_EVENTS_GESTURE_DETECTION_SNAP_SCROLL_CONTROLLER_H_
 
 #include "base/basictypes.h"
 #include "ui/events/gesture_detection/gesture_detection_export.h"
+#include "ui/events/gesture_event_details.h"
 #include "ui/gfx/geometry/point_f.h"
 #include "ui/gfx/geometry/size_f.h"
 #include "ui/gfx/geometry/vector2d_f.h"
 
 namespace ui {
 
 class MotionEvent;
 
 // Port of SnapScrollController.java from Chromium
 // Controls the scroll snapping behavior based on scroll updates.
 class GESTURE_DETECTION_EXPORT SnapScrollController {
  public:
   SnapScrollController(float snap_bound, const gfx::SizeF& display_size);
   ~SnapScrollController();
 
   // Sets the snap scroll mode based on the event type.
   void SetSnapScrollMode(const MotionEvent& event,
                          bool is_scale_gesture_detection_in_progress);
 
   // Updates the snap scroll mode based on the given X and Y distance to be
   // moved on scroll.  If the scroll update is above a threshold, the snapping
   // behavior is reset.
   void UpdateSnapScrollMode(float distance_x, float distance_y);
 
+  GestureEventDetails::ScrollRailState ScrollRailState() const;
+  // TODO(tdresser): remove as part of crbug.com/472223.
   bool IsSnapVertical() const;
   bool IsSnapHorizontal() const;
   bool IsSnappingScrolls() const;
 
  private:
   enum SnapMode { SNAP_NONE, SNAP_PENDING, SNAP_HORIZ, SNAP_VERT };
 
   const float snap_bound_;
   const float channel_distance_;
   SnapMode mode_;
   gfx::PointF down_position_;
   gfx::Vector2dF accumulated_distance_;
 
   DISALLOW_COPY_AND_ASSIGN(SnapScrollController);
 };
 
 }  // namespace ui
 
 #endif  // UI_EVENTS_GESTURE_DETECTION_SNAP_SCROLL_CONTROLLER_H_