Clear MatchedPropertiesCache on StyleRule changes.

third_party/WebKit/Source/core/css/CSSStyleSheet.cpp

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2006, 2007, 2012 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 142 matching lines @@
   m_contents->setMutable();
 
   // Any existing CSSOM wrappers need to be connected to the copied child rules.
   reattachChildRuleCSSOMWrappers();
 }
 
 void CSSStyleSheet::didMutateRules() {
   DCHECK(m_contents->isMutable());
   DCHECK_LE(m_contents->clientSize(), 1u);
 
-  didMutate();
+  Document* owner = ownerDocument();
+  if (!owner)
+    return;
+  if (ownerNode() && ownerNode()->isConnected()) {
+    owner->styleEngine().setNeedsActiveStyleUpdate(ownerNode()->treeScope());
+    if (StyleResolver* resolver = owner->styleEngine().resolver())
+      resolver->invalidateMatchedPropertiesCache();
+  }
 }
 
 void CSSStyleSheet::didMutate() {
   Document* owner = ownerDocument();
   if (!owner)
     return;
   if (ownerNode() && ownerNode()->isConnected())
     owner->styleEngine().setNeedsActiveStyleUpdate(ownerNode()->treeScope());
 }
 
@@ skipping 260 matching lines @@
   visitor->trace(m_deviceDependentMediaQueryResults);
   visitor->trace(m_ownerNode);
   visitor->trace(m_ownerRule);
   visitor->trace(m_mediaCSSOMWrapper);
   visitor->trace(m_childRuleCSSOMWrappers);
   visitor->trace(m_ruleListCSSOMWrapper);
   StyleSheet::trace(visitor);
 }
 
 }  // namespace blink