Fix bug in CSSOM window.scroll api

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

Index: third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp
diff --git a/third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp b/third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp
index 734b962d8ee152ed12ed4eda6a06216ee1e2b55f..65b8ef84bada10f9014fa011d3c4eb7058ec003a 100644
--- a/third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp
+++ b/third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp
@@ -1135,10 +1135,11 @@ void LocalDOMWindow::scrollBy(double x, double y, ScrollBehavior scrollBehavior)
     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);
 }
 
@@ -1206,7 +1207,9 @@ void LocalDOMWindow::scrollTo(const ScrollToOptions& scrollToOptions) const
     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();
 
@@ -1218,7 +1221,7 @@ void LocalDOMWindow::scrollTo(const ScrollToOptions& scrollToOptions) const
 
     ScrollBehavior scrollBehavior = ScrollBehaviorAuto;
     ScrollableArea::scrollBehaviorFromString(scrollToOptions.behavior(), scrollBehavior);
-    ScrollableArea* viewport = host->settings().inertVisualViewport() ? view->layoutViewportScrollableArea() : view->scrollableArea();
+
     viewport->setScrollPosition(DoublePoint(scaledX, scaledY), ProgrammaticScroll, scrollBehavior);
 }