Current work-in-progress crbug.com/567021

third_party/WebKit/Source/core/html/HTMLStyleElement.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2003, 2010 Apple Inc. All rights reserved.
  *           (C) 2007 Rob Buis (buis@kde.org)
  *
  * 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
@@ skipping 39 matching lines @@
 }
 
 void HTMLStyleElement::parseAttribute(const QualifiedName& name,
                                       const AtomicString& oldValue,
                                       const AtomicString& value) {
   if (name == titleAttr && m_sheet && isInDocumentTree()) {
     m_sheet->setTitle(value);
   } else if (name == mediaAttr && isConnected() && document().isActive() &&
              m_sheet) {
     m_sheet->setMediaQueries(MediaQuerySet::create(value));
-    document().styleEngine().setNeedsActiveStyleUpdate(m_sheet.get(),
-                                                       FullStyleUpdate);
+    document().styleEngine().mediaQueriesChangedInScope(treeScope());
   } else {
     HTMLElement::parseAttribute(name, oldValue, value);
   }
 }
 
 void HTMLStyleElement::finishParsingChildren() {
   StyleElement::ProcessingResult result =
       StyleElement::finishParsingChildren(*this);
   HTMLElement::finishParsingChildren();
   if (result == StyleElement::ProcessingFatalError)
@@ skipping 67 matching lines @@
   if (CSSStyleSheet* styleSheet = sheet())
     styleSheet->setDisabled(setDisabled);
 }
 
 DEFINE_TRACE(HTMLStyleElement) {
   StyleElement::trace(visitor);
   HTMLElement::trace(visitor);
 }
 
 }  // namespace blink