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 8e0b0ca35395f3cac48297badb280244cc111290..8bf2a901878752fd92e0ee6a9b6073569023e5fd 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp
@@ -442,6 +442,18 @@ 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());
@@ -1671,6 +1683,12 @@ 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);