Workaround rect-based paint invalidation on ancestor clip change

third_party/WebKit/Source/core/layout/LayoutObject.cpp

Index: third_party/WebKit/Source/core/layout/LayoutObject.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutObject.cpp b/third_party/WebKit/Source/core/layout/LayoutObject.cpp
index 80565df0ef762904c649c481e51d244adfde82f2..6837719b49239e9c671e9745dbda93040da38011 100644
--- a/third_party/WebKit/Source/core/layout/LayoutObject.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutObject.cpp
@@ -1356,6 +1356,11 @@ PaintInvalidationReason LayoutObject::invalidatePaintIfNeeded(PaintInvalidationS
     if (!RuntimeEnabledFeatures::slimmingPaintOffsetCachingEnabled())
         setPreviousPositionFromPaintInvalidationBacking(newLocation);
 
+    if (!shouldCheckForPaintInvalidationRegardlessOfPaintInvalidationState() && !paintInvalidationState.forcedSubtreeInvalidationWithinContainer()) {
+        ASSERT(paintInvalidationState.forcedSubtreeInvalidationRectUpdateWithinContainer());
+        return PaintInvalidationNone;
+    }
+
     PaintInvalidationReason invalidationReason = paintInvalidationReason(paintInvalidationContainer, oldBounds, oldLocation, newBounds, newLocation);
 
     // We need to invalidate the selection before checking for whether we are doing a full invalidation.
@@ -3192,7 +3197,7 @@ void LayoutObject::clearPaintInvalidationState(const PaintInvalidationState& pai
 {
     // paintInvalidationStateIsDirty should be kept in sync with the
     // booleans that are cleared below.
-    ASSERT(paintInvalidationState.forcedSubtreeInvalidationWithinContainer() || paintInvalidationStateIsDirty());
+    ASSERT(paintInvalidationState.forcedSubtreeInvalidationWithinContainer() || paintInvalidationState.forcedSubtreeInvalidationRectUpdateWithinContainer() || paintInvalidationStateIsDirty());
     clearShouldDoFullPaintInvalidation();
     m_bitfields.setChildShouldCheckForPaintInvalidation(false);
     m_bitfields.setNeededLayoutBecauseOfChildren(false);