Use float for scroll offset.

third_party/WebKit/Source/core/page/scrolling/ViewportScrollCallback.cpp

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/page/scrolling/ViewportScrollCallback.h"
 
 #include "core/frame/FrameHost.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/RootFrameViewport.h"
 #include "core/frame/Settings.h"
@@ skipping 16 matching lines @@
 ViewportScrollCallback::~ViewportScrollCallback() {}
 
 DEFINE_TRACE(ViewportScrollCallback) {
   visitor->trace(m_topControls);
   visitor->trace(m_overscrollController);
   visitor->trace(m_rootFrameViewport);
   ScrollStateCallback::trace(visitor);
 }
 
 bool ViewportScrollCallback::shouldScrollTopControls(
-    const FloatSize& delta,
+    const ScrollOffset& delta,
     ScrollGranularity granularity) const {
   if (granularity != ScrollByPixel && granularity != ScrollByPrecisePixel)
     return false;
 
   if (!m_rootFrameViewport)
     return false;
 
-  DoublePoint maxScroll = m_rootFrameViewport->maximumScrollPositionDouble();
-  DoublePoint scrollPosition = m_rootFrameViewport->scrollPositionDouble();
+  ScrollOffset maxScroll = m_rootFrameViewport->maximumScrollOffset();
+  ScrollOffset scrollOffset = m_rootFrameViewport->scrollOffset();
 
   // Always give the delta to the top controls if the scroll is in
   // the direction to show the top controls. If it's in the
   // direction to hide the top controls, only give the delta to the
   // top controls when the frame can scroll.
-  return delta.height() < 0 || scrollPosition.y() < maxScroll.y();
+  return delta.height() < 0 || scrollOffset.height() < maxScroll.height();
 }
 
 bool ViewportScrollCallback::scrollTopControls(ScrollState& state) {
   // Scroll top controls.
   if (m_topControls) {
     if (state.isBeginning())
       m_topControls->scrollBegin();
 
     FloatSize delta(state.deltaX(), state.deltaY());
     ScrollGranularity granularity =
@@ skipping 46 matching lines @@
   // The viewport consumes everything.
   // TODO(bokan): This isn't actually consuming everything but doing so breaks
   // the main thread pull-to-refresh action. crbug.com/607210.
   state.consumeDeltaNative(delta.width() - result.unusedScrollDeltaX,
                            delta.height() - result.unusedScrollDeltaY);
 
   return result;
 }
 
 }  // namespace blink