Optimize outline paint invalidation

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/)
@@ skipping 1833 matching lines @@
         block->setScrollAnchorDisablingStyleChanged(true);
         return;
       }
     }
     object = object->parent();
   }
 }
 
 void LayoutObject::styleDidChange(StyleDifference diff,
                                   const ComputedStyle* oldStyle) {
+  // First assume the outline will be affected. It may be updated when we know
+  // it's not affected.
+  bool hasOutline = m_style->hasOutline();
+  setOutlineMayBeAffectedByDescendants(hasOutline);
+  if (!hasOutline)
+    setPreviousOutlineMayBeAffectedByDescendants(false);
+
   if (s_affectsParentBlock)
     handleDynamicFloatPositionChange(this);
 
   if (!m_parent)
     return;
 
   if (diff.needsFullLayout()) {
     LayoutCounter::layoutObjectStyleChanged(*this, oldStyle, *m_style);
 
     // If the in-flow state of an element is changed, disable scroll
@@ skipping 1628 matching lines @@
     const blink::LayoutObject* root = object1;
     while (root->parent())
       root = root->parent();
     root->showLayoutTreeAndMark(object1, "*", object2, "-", 0);
   } else {
     WTFLogAlways("%s", "Cannot showLayoutTree. Root is (nil)");
   }
 }
 
 #endif