Move preferred stylesheet set out of active sheet update.

third_party/WebKit/Source/core/dom/StyleEngine.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) Research In Motion Limited 2010-2011. All rights reserved.
@@ skipping 509 matching lines @@
     } else {
         StyleSheetContents* contents = result.storedValue->value;
         DCHECK(contents);
         DCHECK(contents->isCacheableForStyleElement());
         DCHECK_EQ(contents->singleOwnerDocument(), e->document());
         styleSheet = CSSStyleSheet::createInline(contents, e, startPosition);
     }
 
     DCHECK(styleSheet);
     styleSheet->setTitle(e->title());
+    if (!e->isInShadowTree())
+        setPreferredStylesheetSetNameIfNotSet(e->title());
     return styleSheet;
 }
 
 CSSStyleSheet* StyleEngine::parseSheet(Element* e, const String& text, TextPosition startPosition)
 {
     CSSStyleSheet* styleSheet = nullptr;
     styleSheet = CSSStyleSheet::createInline(e, KURL(), startPosition, e->document().characterSet());
     styleSheet->contents()->parseStringAtPosition(text, startPosition);
     return styleSheet;
 }
@@ skipping 221 matching lines @@
 
 DEFINE_TRACE_WRAPPERS(StyleEngine)
 {
     for (auto sheet : m_injectedAuthorStyleSheets) {
         visitor->traceWrappers(sheet);
     }
     visitor->traceWrappers(m_documentStyleSheetCollection);
 }
 
 } // namespace blink