Get rid of clampScrollOffset and make maximumScrollPosition sane.

Source/core/paint/DeprecatedPaintLayerScrollableArea.h

Index: Source/core/paint/DeprecatedPaintLayerScrollableArea.h
diff --git a/Source/core/paint/DeprecatedPaintLayerScrollableArea.h b/Source/core/paint/DeprecatedPaintLayerScrollableArea.h
index c7b2756f8cfd8ba57716c3328f8f05e0277ffb08..0a0225dc7f1943af61af0166e8f4a79ea1c360ba 100644
--- a/Source/core/paint/DeprecatedPaintLayerScrollableArea.h
+++ b/Source/core/paint/DeprecatedPaintLayerScrollableArea.h
@@ -132,7 +132,12 @@ public:
     // FIXME: We shouldn't allow access to m_overflowRect outside this class.
     LayoutRect overflowRect() const { return m_overflowRect; }
 
-    void scrollToOffset(const DoubleSize& scrollOffset, ScrollOffsetClamping = ScrollOffsetUnclamped, ScrollBehavior = ScrollBehaviorInstant);
+    void scrollToPosition(const DoublePoint& scrollPosition, ScrollOffsetClamping = ScrollOffsetUnclamped, ScrollBehavior = ScrollBehaviorInstant);
+
+    void scrollToOffset(const DoubleSize& scrollOffset, ScrollOffsetClamping clamp = ScrollOffsetUnclamped, ScrollBehavior scrollBehavior = ScrollBehaviorInstant)
+    {
+        scrollToPosition(-scrollOrigin() + scrollOffset, clamp, scrollBehavior);
+    }
 
     void scrollToXOffset(double x, ScrollOffsetClamping clamp = ScrollOffsetUnclamped, ScrollBehavior scrollBehavior = ScrollBehaviorInstant)
     {
@@ -243,10 +248,6 @@ private:
 
     void computeScrollDimensions();
 
-    // TODO(bokan): This method hides the base class version and is subtly different.
-    // Should be unified.
-    DoubleSize clampScrollOffset(const DoubleSize&) const;
-
     void setScrollOffset(const IntPoint&, ScrollType) override;
     void setScrollOffset(const DoublePoint&, ScrollType) override;