Delay scrollContents until the next paint

Source/platform/scroll/ScrollView.cpp

Index: Source/platform/scroll/ScrollView.cpp
diff --git a/Source/platform/scroll/ScrollView.cpp b/Source/platform/scroll/ScrollView.cpp
index 4b778ab6951c066d3e4ed868b0a655f81cec7463..4608aeceb358b06a16fd0f547c2217f4b7aeb187 100644
--- a/Source/platform/scroll/ScrollView.cpp
+++ b/Source/platform/scroll/ScrollView.cpp
@@ -274,9 +274,7 @@ void ScrollView::scrollTo(const IntSize& newOffset)
     if (scrollbarsSuppressed())
         return;
 
-    repaintFixedElementsAfterScrolling();
-    scrollContents(scrollDelta);
-    updateFixedElementsAfterScrolling();
+    m_pendingScrollDelta += scrollDelta;
 }
 
 void ScrollView::setScrollPosition(const IntPoint& scrollPoint)
@@ -515,6 +513,15 @@ IntRect ScrollView::rectToCopyOnScroll() const
     return scrollViewRect;
 }
 
+void ScrollView::scrollContentsIfNeeded()
+{
+    if (m_pendingScrollDelta.isZero())
+        return;
+    IntSize scrollDelta = m_pendingScrollDelta;
+    m_pendingScrollDelta = IntSize();
+    scrollContents(scrollDelta);
+}
+
 void ScrollView::scrollContents(const IntSize& scrollDelta)
 {
     HostWindow* window = hostWindow();