Workaround rect-based paint invalidation on ancestor clip change

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 1338 matching lines @@
     if (paintInvalidationContainer.usesCompositedScrolling() && &paintInvalidationContainer != this) {
         LayoutSize inverseOffset(toLayoutBox(&paintInvalidationContainer)->scrolledContentOffset());
         newLocation.move(inverseOffset);
         newBounds.move(inverseOffset);
     }
 
     setPreviousPaintInvalidationRect(newBounds);
     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.
     // This is because we need to update the old rect regardless.
     invalidateSelectionIfNeeded(paintInvalidationContainer, invalidationReason);
 
     TRACE_EVENT2(TRACE_DISABLED_BY_DEFAULT("blink.invalidation"), "LayoutObject::invalidatePaintIfNeeded()",
         "object", this->debugName().ascii(),
         "info", jsonObjectForOldAndNewRects(oldBounds, oldLocation, newBounds, newLocation));
 
@@ skipping 1816 matching lines @@
         return;
     m_bitfields.setMayNeedPaintInvalidation(true);
     markContainerChainForPaintInvalidation();
     frame()->page()->animator().scheduleVisualUpdate(); // In case that this is called outside of FrameView::updateLayoutAndStyleForPainting().
 }
 
 void LayoutObject::clearPaintInvalidationState(const PaintInvalidationState& paintInvalidationState)
 {
     // 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);
     m_bitfields.setShouldInvalidateOverflowForPaint(false);
     m_bitfields.setMayNeedPaintInvalidation(false);
     m_bitfields.setShouldInvalidateSelection(false);
 }
 
 bool LayoutObject::isAllowedToModifyLayoutTreeStructure(Document& document)
 {
@@ skipping 188 matching lines @@
         const blink::LayoutObject* root = object1;
         while (root->parent())
             root = root->parent();
         root->showLayoutTreeAndMark(object1, "*", object2, "-", 0);
     } else {
         fprintf(stderr, "Cannot showLayoutTree. Root is (nil)\n");
     }
 }
 
 #endif