Implement PaintLayer::scrollsWithViewport for SPv2.

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

Index: third_party/WebKit/Source/core/frame/FrameView.cpp
diff --git a/third_party/WebKit/Source/core/frame/FrameView.cpp b/third_party/WebKit/Source/core/frame/FrameView.cpp
index 8f14f007e448d32c2a6764b3b3b04a6adad430ce..de2724a16ae7e58e013cde03ec403efd8a4e5f0e 100644
--- a/third_party/WebKit/Source/core/frame/FrameView.cpp
+++ b/third_party/WebKit/Source/core/frame/FrameView.cpp
@@ -2878,8 +2878,11 @@ void FrameView::updateLifecyclePhasesInternal(
       if (targetState >= DocumentLifecycle::PrePaintClean) {
         if (!RuntimeEnabledFeatures::slimmingPaintInvalidationEnabled())
           invalidateTreeIfNeededRecursive();
-        if (view.compositor()->inCompositingMode())
-          scrollingCoordinator()->updateAfterCompositingChangeIfNeeded();
+
+        if (!RuntimeEnabledFeatures::slimmingPaintV2Enabled()) {
+          if (view.compositor()->inCompositingMode())
+            scrollingCoordinator()->updateAfterCompositingChangeIfNeeded();
+        }
 
         updateCompositedSelectionIfNeeded();
       }