Setting the link title may change the preferred set.

third_party/WebKit/Source/core/html/HTMLLinkElement.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2008, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2011 Google 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.
@@ skipping 11 matching lines @@
  */
 
 #ifndef HTMLLinkElement_h
 #define HTMLLinkElement_h
 
 #include "core/CoreExport.h"
 #include "core/css/CSSStyleSheet.h"
 #include "core/dom/DOMTokenList.h"
 #include "core/dom/IconURL.h"
 #include "core/dom/IncrementLoadEventDelayCount.h"
-#include "core/dom/StyleEngineContext.h"
+#include "core/dom/StyleEngine.h"
 #include "core/fetch/ResourceOwner.h"
 #include "core/fetch/StyleSheetResource.h"
 #include "core/fetch/StyleSheetResourceClient.h"
 #include "core/html/HTMLElement.h"
 #include "core/html/LinkRelAttribute.h"
 #include "core/html/LinkResource.h"
 #include "core/html/RelList.h"
 #include "core/loader/LinkLoader.h"
 #include "core/loader/LinkLoaderClient.h"
 #include <memory>
@@ skipping 25 matching lines @@
     void process() override;
     void ownerRemoved() override;
     bool hasLoaded() const override { return m_loadedSheet; }
     DECLARE_VIRTUAL_TRACE();
 
     void startLoadingDynamicSheet();
     void notifyLoadedSheetAndAllCriticalSubresources(Node::LoadedSheetErrorStatus);
     bool sheetLoaded();
 
     void setDisabledState(bool);
-    void setSheetTitle(const String&);
+    void setSheetTitle(const String&, StyleEngine::ActiveSheetsUpdate = StyleEngine::DontUpdateActiveSheets);
 
     bool styleSheetIsLoading() const;
     bool hasSheet() const { return m_sheet; }
     bool isDisabled() const { return m_disabledState == Disabled; }
     bool isEnabledViaScript() const { return m_disabledState == EnabledViaScript; }
     bool isUnset() const { return m_disabledState == Unset; }
 
     CSSStyleSheet* sheet() const { return m_sheet.get(); }
 
 private:
@@ skipping 136 matching lines @@
     Member<RelList> m_relList;
     LinkRelAttribute m_relAttribute;
     String m_scope;
 
     bool m_createdByParser;
 };
 
 } // namespace blink
 
 #endif // HTMLLinkElement_h