Current work-in-progress crbug.com/567021

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 141 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(PartialRuleUpdate);
+  didMutate();
 }
 
-void CSSStyleSheet::didMutate(StyleSheetUpdateType updateType) {
+void CSSStyleSheet::didMutate() {
   Document* owner = ownerDocument();
   if (!owner)
     return;
-
-  // Need FullStyleUpdate when insertRule or deleteRule,
-  // because StyleSheetCollection::analyzeStyleSheetChange cannot detect partial
-  // rule update.
-  StyleResolverUpdateMode updateMode =
-      updateType != PartialRuleUpdate ? AnalyzedStyleUpdate : FullStyleUpdate;
-  owner->styleEngine().setNeedsActiveStyleUpdate(this, updateMode);
+  if (ownerNode() && ownerNode()->isConnected())
+    owner->styleEngine().setNeedsActiveStyleUpdate(ownerNode()->treeScope());
 }
 
 void CSSStyleSheet::reattachChildRuleCSSOMWrappers() {
   for (unsigned i = 0; i < m_childRuleCSSOMWrappers.size(); ++i) {
     if (!m_childRuleCSSOMWrappers[i])
       continue;
     m_childRuleCSSOMWrappers[i]->reattach(m_contents->ruleAt(i));
   }
 }
 
@@ skipping 34 matching lines @@
     m_childRuleCSSOMWrappers.grow(ruleCount);
   DCHECK_EQ(m_childRuleCSSOMWrappers.size(), ruleCount);
 
   Member<CSSRule>& cssRule = m_childRuleCSSOMWrappers[index];
   if (!cssRule)
     cssRule = m_contents->ruleAt(index)->createCSSOMWrapper(this);
   return cssRule.get();
 }
 
 void CSSStyleSheet::clearOwnerNode() {
-  didMutate(EntireStyleSheetUpdate);
+  didMutate();
   if (m_ownerNode)
     m_contents->unregisterClient(this);
   m_ownerNode = nullptr;
 }
 
 bool CSSStyleSheet::canAccessRules() const {
   if (m_isInlineStylesheet)
     return true;
   KURL baseURL = m_contents->baseURL();
   if (baseURL.isEmpty())
@@ skipping 197 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