Removed main-thread one dimensional scrolling paths.

third_party/WebKit/Source/platform/scroll/Scrollbar.cpp

 /*
  * Copyright (C) 2004, 2006, 2008 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 184 matching lines @@
     if (m_pressedPart == ThumbPart || m_pressedPart == NoPart)
         return;
 
     // Handle the track.
     if ((m_pressedPart == BackTrackPart || m_pressedPart == ForwardTrackPart) && thumbWillBeUnderMouse()) {
         setHoveredPart(ThumbPart);
         return;
     }
 
     // Handle the arrows and track.
-    if (m_scrollableArea && m_scrollableArea->userScroll(pressedPartScrollDirectionPhysical(), pressedPartScrollGranularity()).didScroll)
+    if (m_scrollableArea && m_scrollableArea->userScroll(pressedPartScrollGranularity(), toScrollDelta(pressedPartScrollDirectionPhysical(), 1)).didScroll())
         startTimerIfNeeded(delay);
 }
 
 void Scrollbar::startTimerIfNeeded(double delay)
 {
     // Don't do anything for the thumb.
     if (m_pressedPart == ThumbPart)
         return;
 
     // Handle the track.  We halt track scrolling once the thumb is level
@@ skipping 130 matching lines @@
         return true;
     case PlatformEvent::GestureScrollEnd:
     case PlatformEvent::GestureLongPress:
     case PlatformEvent::GestureFlingStart:
         m_scrollPos = 0;
         m_pressedPos = 0;
         setPressedPart(NoPart);
         return false;
     case PlatformEvent::GestureTap: {
         if (m_pressedPart != ThumbPart && m_pressedPart != NoPart && m_scrollableArea
-            && m_scrollableArea->userScroll(pressedPartScrollDirectionPhysical(), pressedPartScrollGranularity()).didScroll) {
+            && m_scrollableArea->userScroll(pressedPartScrollGranularity(), toScrollDelta(pressedPartScrollDirectionPhysical(), 1)).didScroll()) {
             return true;
         }
         m_scrollPos = 0;
         m_pressedPos = 0;
         setPressedPart(NoPart);
         return false;
     }
     default:
         // By default, we assume that gestures don't deselect the scrollbar.
         return true;
@@ skipping 213 matching lines @@
         invalidParts = AllParts;
     if (invalidParts & ~ThumbPart)
         m_trackNeedsRepaint = true;
     if (invalidParts & ThumbPart)
         m_thumbNeedsRepaint = true;
     if (m_scrollableArea)
         m_scrollableArea->setScrollbarNeedsPaintInvalidation(orientation());
 }
 
 } // namespace blink