Invalidate paint properties on paint offset changes

third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp

Index: third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp
diff --git a/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp b/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp
index 21ca56bf379e6ffeed9cc33804555fc0ee99ec8c..a6adbe381105a5087e2a60c4f45c7312390da0fa 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp
@@ -444,6 +444,18 @@ void PaintLayerScrollableArea::updateScrollOffset(const ScrollOffset& newOffset,
     box().setShouldDoFullPaintInvalidationIncludingNonCompositingDescendants();
   }
 
+  if (RuntimeEnabledFeatures::slimmingPaintInvalidationEnabled()) {
+    // The scrollOffsetTranslation paint property depends on the scroll offset.
+    // (see: PaintPropertyTreeBuilder.updateProperties(FrameView&,...) and
+    // PaintPropertyTreeBuilder.updateScrollAndScrollTranslation).
+    if (!RuntimeEnabledFeatures::rootLayerScrollingEnabled() &&
+        layer()->isRootLayer()) {
+      frameView->setNeedsPaintPropertyUpdate();
+    } else {
+      box().setNeedsPaintPropertyUpdate();
+    }
+  }
+
   // Schedule the scroll DOM event.
   if (box().node())
     box().node()->document().enqueueScrollEventForNode(box().node());
@@ -1673,6 +1685,12 @@ void PaintLayerScrollableArea::updateScrollableAreaSet(bool hasOverflow) {
   if (didScrollOverflow == scrollsOverflow())
     return;
 
+  if (RuntimeEnabledFeatures::slimmingPaintInvalidationEnabled()) {
+    // The scroll and scroll offset properties depend on |scrollsOverflow| (see:
+    // PaintPropertyTreeBuilder::updateScrollAndScrollTranslation).
+    box().setNeedsPaintPropertyUpdate();
+  }
+
   if (m_scrollsOverflow) {
     DCHECK(canHaveOverflowScrollbars(box()));
     frameView->addScrollableArea(this);