Removed main-thread one dimensional scrolling paths.

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

 /*
  * Copyright (c) 2010, Google Inc. All rights reserved.
  * Copyright (C) 2008, 2011 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 139 matching lines @@
         return documentStep(orientation);
     case ScrollByPixel:
     case ScrollByPrecisePixel:
         return pixelStep(orientation);
     default:
         ASSERT_NOT_REACHED();
         return 0.0f;
     }
 }
 
-ScrollResultOneDimensional ScrollableArea::userScroll(ScrollDirectionPhysical direction, ScrollGranularity granularity, float delta)
+ScrollResult ScrollableArea::userScroll(ScrollGranularity granularity, const FloatSize& delta)
 {
-    ScrollbarOrientation orientation = scrollbarOrientationFromDirection(direction);
-    if (!userInputScrollable(orientation))
-        return ScrollResultOneDimensional(false, delta);
+    float stepX = scrollStep(granularity, HorizontalScrollbar);
+    float stepY = scrollStep(granularity, VerticalScrollbar);
+
+    FloatSize pixelDelta(delta);
+    pixelDelta.scale(stepX, stepY);
+
+    FloatSize scrollableAxisDelta(
+        userInputScrollable(HorizontalScrollbar) ? pixelDelta.width() : 0,
+        userInputScrollable(VerticalScrollbar) ? pixelDelta.height() : 0);
+
+    if (scrollableAxisDelta.isZero()) {
+        return ScrollResult(
+            false,
+            false,
+            pixelDelta.width(),
+            pixelDelta.height());
+    }
 
     cancelProgrammaticScrollAnimation();
 
-    float step = scrollStep(granularity, orientation);
+    ScrollResult result = scrollAnimator().userScroll(granularity, pixelDelta);
 
-    if (direction == ScrollUp || direction == ScrollLeft)
-        delta = -delta;
+    // Delta that wasn't scrolled because the axis is !userInputScrollable
+    // should count as unusedScrollDelta.
+    FloatSize unscrollableAxisDelta = pixelDelta - scrollableAxisDelta;
+    result.unusedScrollDeltaX += unscrollableAxisDelta.width();
+    result.unusedScrollDeltaY += unscrollableAxisDelta.height();
 
-    return scrollAnimator().userScroll(orientation, granularity, step * delta);
+    return result;
 }
 
 void ScrollableArea::setScrollPosition(const DoublePoint& position, ScrollType scrollType, ScrollBehavior behavior)
 {
     if (behavior == ScrollBehaviorAuto)
         behavior = scrollBehaviorStyle();
 
     switch (scrollType) {
     case CompositorScroll:
     case AnchoringScroll:
@@ skipping 433 matching lines @@
         std::max(0, size.height() - horizontalScrollbarHeight));
 }
 
 DEFINE_TRACE(ScrollableArea)
 {
     visitor->trace(m_scrollAnimator);
     visitor->trace(m_programmaticScrollAnimator);
 }
 
 } // namespace blink