Removed main-thread one dimensional scrolling paths.

third_party/WebKit/Source/platform/scroll/ScrollAnimatorBase.h

Index: third_party/WebKit/Source/platform/scroll/ScrollAnimatorBase.h
diff --git a/third_party/WebKit/Source/platform/scroll/ScrollAnimatorBase.h b/third_party/WebKit/Source/platform/scroll/ScrollAnimatorBase.h
index c50eac24ec0a3b4f63f89b4a662ae7b668e2d50f..68d78057f6ca6dd50cd67e231084252ebd700b08 100644
--- a/third_party/WebKit/Source/platform/scroll/ScrollAnimatorBase.h
+++ b/third_party/WebKit/Source/platform/scroll/ScrollAnimatorBase.h
@@ -54,12 +54,13 @@ public:
 
     virtual void dispose() { }
 
-    // Computes a scroll destination for the given parameters.  The returned
-    // ScrollResultOneDimensional will have didScroll set to false if already at
-    // the destination.  Otherwise, starts scrolling towards the destination and
-    // didScroll is true.  Scrolling may be immediate or animated. The base
-    // class implementation always scrolls immediately, never animates.
-    virtual ScrollResultOneDimensional userScroll(ScrollbarOrientation, ScrollGranularity, float delta);
+    // A possibly animated scroll. The base class implementation always scrolls
+    // immediately, never animates. If the scroll is animated and currently the
+    // animator has an in-progress animation, the ScrollResult will always return
+    // no unusedDelta and didScroll=true, i.e. fully consuming the scroll request.
+    // This makes animations latch to a single scroller. Note, the semantics are
+    // currently somewhat different on Mac - see ScrollAnimatorMac.mm.
+    virtual ScrollResult userScroll(ScrollGranularity, const FloatSize& delta);
 
     virtual void scrollToOffsetWithoutAnimation(const FloatPoint&);
 
@@ -73,7 +74,7 @@ public:
 
     // Returns how much of pixelDelta will be used by the underlying scrollable
     // area.
-    virtual float computeDeltaToConsume(ScrollbarOrientation, float pixelDelta) const;
+    virtual FloatSize computeDeltaToConsume(const FloatSize& delta) const;
 
 
     // ScrollAnimatorCompositorCoordinator implementation.
@@ -118,11 +119,9 @@ protected:
 
     virtual void notifyPositionChanged();
 
-    float clampScrollPosition(ScrollbarOrientation, float) const;
-
     RawPtrWillBeMember<ScrollableArea> m_scrollableArea;
-    float m_currentPosX; // We avoid using a FloatPoint in order to reduce
-    float m_currentPosY; // subclass code complexity.
+
+    FloatPoint m_currentPos;
 };
 
 } // namespace blink