Use float for scroll offset.

third_party/WebKit/Source/platform/graphics/GraphicsLayer.cpp

Index: third_party/WebKit/Source/platform/graphics/GraphicsLayer.cpp
diff --git a/third_party/WebKit/Source/platform/graphics/GraphicsLayer.cpp b/third_party/WebKit/Source/platform/graphics/GraphicsLayer.cpp
index 898e54807f2c45f42e1898c63a7d5ba1e10b2d66..9b5d7441f068f32f5e388e98b84f898c26c8785e 100644
--- a/third_party/WebKit/Source/platform/graphics/GraphicsLayer.cpp
+++ b/third_party/WebKit/Source/platform/graphics/GraphicsLayer.cpp
@@ -1117,16 +1117,16 @@ void GraphicsLayer::setScrollableArea(ScrollableArea* scrollableArea,
 
 void GraphicsLayer::didScroll() {
   if (m_scrollableArea) {
-    DoublePoint newPosition =
-        -m_scrollableArea->scrollOrigin() +
-        toDoubleSize(m_layer->layer()->scrollPositionDouble());
+    ScrollOffset newOffset =
+        toFloatSize(m_layer->layer()->scrollPositionDouble() -
+                    m_scrollableArea->scrollOrigin());
 
-    // FrameView::setScrollPosition() doesn't work for compositor commits
+    // FrameView::setScrollOffset() doesn't work for compositor commits
     // (interacts poorly with programmatic scroll animations) so we need to use
     // the ScrollableArea version. The FrameView method should go away soon
     // anyway.
-    m_scrollableArea->ScrollableArea::setScrollPosition(newPosition,
-                                                        CompositorScroll);
+    m_scrollableArea->ScrollableArea::setScrollOffset(newOffset,
+                                                      CompositorScroll);
   }
 }