Add rails to input wheel events.

Source/core/frame/PinchViewport.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 432 matching lines @@
 {
     FrameView* view = mainFrame()->view();
     ScrollResult viewScrollResult = view->wheelEvent(event);
 
     // The virtual viewport will only accept pixel scrolls.
     if (!event.canScroll() || event.granularity() == ScrollByPageWheelEvent)
         return viewScrollResult;
 
     // Move the location by the negative of the remaining scroll delta.
     FloatPoint oldOffset = m_offset;
-    FloatPoint locationDelta = viewScrollResult.didScroll ?
-        -FloatPoint(viewScrollResult.unusedScrollDeltaX, viewScrollResult.unusedScrollDeltaY) :
-        -FloatPoint(event.deltaX(), event.deltaY());
+    FloatPoint locationDelta;
+    if (viewScrollResult.didScroll) {
+        locationDelta = -FloatPoint(viewScrollResult.unusedScrollDeltaX, viewScrollResult.unusedScrollDeltaY);
+    } else {
+        if (event.railsMode() != PlatformEvent::RailsModeVertical)
+            locationDelta.setX(-event.deltaX());
+        if (event.railsMode() != PlatformEvent::RailsModeHorizontal)
+            locationDelta.setY(-event.deltaY());
+    }
     move(locationDelta);
 
     FloatPoint usedLocationDelta(m_offset - oldOffset);
     if (!viewScrollResult.didScroll && usedLocationDelta == FloatPoint::zero())
         return ScrollResult(false);
 
     FloatPoint unusedLocationDelta(locationDelta - usedLocationDelta);
     return ScrollResult(true, -unusedLocationDelta.x(), -unusedLocationDelta.y());
 }
 
@@ skipping 167 matching lines @@
     } else if (graphicsLayer == m_rootTransformLayer) {
         name =  "Root Transform Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace blink