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 653415b131b29c6413086248638b5168ade0a544..03f135fc7446f25369989205fb4250f017bfa301 100644
--- a/third_party/WebKit/Source/core/frame/FrameView.cpp
+++ b/third_party/WebKit/Source/core/frame/FrameView.cpp
@@ -2870,8 +2870,11 @@ void FrameView::updateLifecyclePhasesInternal(
       if (targetState >= DocumentLifecycle::PrePaintClean) {
         if (!RuntimeEnabledFeatures::slimmingPaintInvalidationEnabled())
           invalidateTreeIfNeededRecursive();
-        if (view.compositor()->inCompositingMode())
-          scrollingCoordinator()->updateAfterCompositingChangeIfNeeded();
+
+        if (!RuntimeEnabledFeatures::slimmingPaintV2Enabled()) {

[chrishtr, 2016/12/06 23:56:07]

This code is not needed for SPv2, and tries to call sticksToViewport at an
illegal lifecycle phase.

+          if (view.compositor()->inCompositingMode())
+            scrollingCoordinator()->updateAfterCompositingChangeIfNeeded();
+        }
 
         updateCompositedSelectionIfNeeded();
       }