Use float for scroll offset.

third_party/WebKit/Source/core/layout/LayoutBox.h

Index: third_party/WebKit/Source/core/layout/LayoutBox.h
diff --git a/third_party/WebKit/Source/core/layout/LayoutBox.h b/third_party/WebKit/Source/core/layout/LayoutBox.h
index cdde731ad1fc0b844582d2feea77321460922761..14a63f9ff7bdde5ae944169bd46e8f345dcc3e08 100644
--- a/third_party/WebKit/Source/core/layout/LayoutBox.h
+++ b/third_party/WebKit/Source/core/layout/LayoutBox.h
@@ -547,9 +547,9 @@ class CORE_EXPORT LayoutBox : public LayoutBoxModelObject {
   virtual void setScrollLeft(LayoutUnit);
   virtual void setScrollTop(LayoutUnit);
 
-  void scrollToOffset(const DoubleSize&,
-                      ScrollBehavior = ScrollBehaviorInstant);
-  void scrollByRecursively(const DoubleSize& delta);
+  void scrollToPosition(const FloatPoint&,

[bokan, 2016/10/02 19:47:51]

Why FloatPoint instead of ScrollOffset?

[szager1, 2016/10/05 07:43:36]

The convention I'm using is:

'position' is a point in the coordinate system of the overflow rect.
'offset' is a distance from the scroll origin.

Using a Point type is intuitive for something called 'position', and it also
helps prevent (via static type checking) inadvertently using the wrong quantity
in code.

[bokan, 2016/10/06 22:32:17]

Acknowledged.

+                        ScrollBehavior = ScrollBehaviorInstant);
+  void scrollByRecursively(const ScrollOffset& delta);
   // If makeVisibleInVisualViewport is set, the visual viewport will be scrolled
   // if required to make the rect visible.
   void scrollRectToVisible(const LayoutRect&,