Fix bug in CSSOM window.scroll api

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

 /*
  * Copyright (C) 2006, 2007, 2008, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 1117 matching lines @@
     if (!view)
         return;
 
     FrameHost* host = frame()->host();
     if (!host)
         return;
 
     x = ScrollableArea::normalizeNonFiniteScroll(x);
     y = ScrollableArea::normalizeNonFiniteScroll(y);
 
-    DoublePoint currentOffset = view->scrollableArea()->scrollPositionDouble();
+    ScrollableArea* viewport = host->settings().inertVisualViewport() ? view->layoutViewportScrollableArea() : view->scrollableArea();
+
+    DoublePoint currentOffset = viewport->scrollPositionDouble();
     DoubleSize scaledDelta(x * frame()->pageZoomFactor(), y * frame()->pageZoomFactor());
 
-    ScrollableArea* viewport = host->settings().inertVisualViewport() ? view->layoutViewportScrollableArea() : view->scrollableArea();
     viewport->setScrollPosition(currentOffset + scaledDelta, ProgrammaticScroll, scrollBehavior);
 }
 
 void LocalDOMWindow::scrollBy(const ScrollToOptions& scrollToOptions) const
 {
     double x = 0.0;
     double y = 0.0;
     if (scrollToOptions.hasLeft())
         x = scrollToOptions.left();
     if (scrollToOptions.hasTop())
@@ skipping 47 matching lines @@
     if (!scrollToOptions.hasLeft()
         || !scrollToOptions.hasTop()
         || scrollToOptions.left()
         || scrollToOptions.top()) {
         document()->updateLayoutIgnorePendingStylesheets();
     }
 
     double scaledX = 0.0;
     double scaledY = 0.0;
 
-    DoublePoint currentOffset = view->scrollableArea()->scrollPositionDouble();
+    ScrollableArea* viewport = host->settings().inertVisualViewport() ? view->layoutViewportScrollableArea() : view->scrollableArea();
+
+    DoublePoint currentOffset = viewport->scrollPositionDouble();
     scaledX = currentOffset.x();
     scaledY = currentOffset.y();
 
     if (scrollToOptions.hasLeft())
         scaledX = ScrollableArea::normalizeNonFiniteScroll(scrollToOptions.left()) * frame()->pageZoomFactor();
 
     if (scrollToOptions.hasTop())
         scaledY = ScrollableArea::normalizeNonFiniteScroll(scrollToOptions.top()) * frame()->pageZoomFactor();
 
     ScrollBehavior scrollBehavior = ScrollBehaviorAuto;
     ScrollableArea::scrollBehaviorFromString(scrollToOptions.behavior(), scrollBehavior);
-    ScrollableArea* viewport = host->settings().inertVisualViewport() ? view->layoutViewportScrollableArea() : view->scrollableArea();
+
     viewport->setScrollPosition(DoublePoint(scaledX, scaledY), ProgrammaticScroll, scrollBehavior);
 }
 
 void LocalDOMWindow::moveBy(int x, int y) const
 {
     if (!frame() || !frame()->isMainFrame())
         return;
 
     FrameHost* host = frame()->host();
     if (!host)
@@ skipping 295 matching lines @@
 {
     // If the LocalDOMWindow still has a frame reference, that frame must point
     // back to this LocalDOMWindow: otherwise, it's easy to get into a situation
     // where script execution leaks between different LocalDOMWindows.
     if (m_frameObserver->frame())
         ASSERT_WITH_SECURITY_IMPLICATION(m_frameObserver->frame()->domWindow() == this);
     return m_frameObserver->frame();
 }
 
 } // namespace blink