Current work-in-progress crbug.com/567021

third_party/WebKit/Source/core/html/HTMLLinkElement.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, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Rob Buis (rwlbuis@gmail.com)
  * 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
@@ skipping 287 matching lines @@
     if (!insertionPoint->inShadowIncludingDocument())
         return;
 
     m_linkLoader->released();
 
     if (m_isInShadowTree) {
         ASSERT(!linkStyle() || !linkStyle()->hasSheet());
         return;
     }
     document().styleEngine().removeStyleSheetCandidateNode(this);
-
-    StyleSheet* removedSheet = sheet();
-
     if (m_link)
         m_link->ownerRemoved();
-
-    document().styleEngine().setNeedsActiveStyleUpdate(removedSheet, FullStyleUpdate);
 }
 
 void HTMLLinkElement::finishParsingChildren()
 {
     m_createdByParser = false;
     HTMLElement::finishParsingChildren();
 }
 
 bool HTMLLinkElement::styleSheetIsLoading() const
 {
@@ skipping 429 matching lines @@
         }
         setResource(CSSStyleSheetResource::fetch(request, document().fetcher()));
 
         if (m_loading && !resource()) {
             // The request may have been denied if (for example) the stylesheet is local and the document is remote, or if there was a Content Security Policy Failure.
             // setCSSStyleSheet() can be called synchronuosly in setResource() and thus resource() is null and |m_loading| is false in such cases even if the request succeeds.
             m_loading = false;
             removePendingSheet();
             notifyLoadedSheetAndAllCriticalSubresources(Node::ErrorOccurredLoadingSubresource);
         }
+        String title = m_owner->title();
+        if (!title.isEmpty() && !m_owner->isAlternate() && m_disabledState != EnabledViaScript)
+            document().styleEngine().setPreferredStylesheetSetNameIfNotSet(title);
     } else if (m_sheet) {
         // we no longer contain a stylesheet, e.g. perhaps rel or type was changed
-        StyleSheet* removedSheet = m_sheet.get();
         clearSheet();
-        document().styleEngine().setNeedsActiveStyleUpdate(removedSheet, FullStyleUpdate);
+        if (m_owner->inShadowIncludingDocument())
+            document().styleEngine().setNeedsActiveStyleUpdate(m_owner->treeScope());
     }
 }
 
 void LinkStyle::setSheetTitle(const String& title)
 {
     if (m_sheet)
         m_sheet->setTitle(title);
 }
 
 void LinkStyle::ownerRemoved()
 {
     if (m_sheet)
         clearSheet();
 
     if (styleSheetIsLoading())
         removePendingSheet();
 }
 
 DEFINE_TRACE(LinkStyle)
 {
     visitor->trace(m_sheet);
     LinkResource::trace(visitor);
     ResourceOwner<StyleSheetResource>::trace(visitor);
 }
 
 } // namespace blink