Use float for scroll offset.

third_party/WebKit/Source/core/frame/DOMVisualViewport.cpp

 /*
  * Copyright (C) 2016 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *  * Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  *  * Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 37 matching lines @@
 }
 
 const AtomicString& DOMVisualViewport::interfaceName() const {
   return EventTargetNames::DOMVisualViewport;
 }
 
 ExecutionContext* DOMVisualViewport::getExecutionContext() const {
   return m_window->getExecutionContext();
 }
 
-double DOMVisualViewport::scrollLeft() {
+float DOMVisualViewport::scrollLeft() {
   LocalFrame* frame = m_window->frame();
   if (!frame || !frame->isMainFrame())
     return 0;
 
   if (FrameHost* host = frame->host())
     return host->visualViewport().scrollLeft();
 
   return 0;
 }
 
-double DOMVisualViewport::scrollTop() {
+float DOMVisualViewport::scrollTop() {
   LocalFrame* frame = m_window->frame();
   if (!frame || !frame->isMainFrame())
     return 0;
 
   if (FrameHost* host = frame->host())
     return host->visualViewport().scrollTop();
 
   return 0;
 }
 
-double DOMVisualViewport::pageX() {
+float DOMVisualViewport::pageX() {
   LocalFrame* frame = m_window->frame();
   if (!frame)
     return 0;
 
   FrameView* view = frame->view();
   if (!view)
     return 0;
 
   frame->document()->updateStyleAndLayoutIgnorePendingStylesheets();
-  double viewportX = view->getScrollableArea()->scrollPositionDouble().x();
+  float viewportX = view->getScrollableArea()->scrollOffset().width();
   return adjustScrollForAbsoluteZoom(viewportX, frame->pageZoomFactor());
 }
 
-double DOMVisualViewport::pageY() {
+float DOMVisualViewport::pageY() {
   LocalFrame* frame = m_window->frame();
   if (!frame)
     return 0;
 
   FrameView* view = frame->view();
   if (!view)
     return 0;
 
   frame->document()->updateStyleAndLayoutIgnorePendingStylesheets();
-  double viewportY = view->getScrollableArea()->scrollPositionDouble().y();
+  float viewportY = view->getScrollableArea()->scrollOffset().height();
   return adjustScrollForAbsoluteZoom(viewportY, frame->pageZoomFactor());
 }
 
 double DOMVisualViewport::clientWidth() {
   LocalFrame* frame = m_window->frame();
   if (!frame)
     return 0;
 
   if (!frame->isMainFrame()) {
     FloatSize viewportSize = m_window->getViewportSize(ExcludeScrollbars);
@@ skipping 32 matching lines @@
   if (!frame->isMainFrame())
     return 1;
 
   if (FrameHost* host = m_window->frame()->host())
     return host->visualViewport().pageScale();
 
   return 0;
 }
 
 }  // namespace blink