Current work-in-progress crbug.com/567021

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

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/html/LinkStyle.h"
 
 #include "core/css/StyleSheetContents.h"
 #include "core/fetch/CSSStyleSheetResource.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/SubresourceIntegrity.h"
@@ skipping 288 matching lines @@
   }
 
   if (!m_owner->shouldLoadLink())
     return Bail;
 
   m_loading = true;
 
   String title = m_owner->title();
   if (!title.isEmpty() && !m_owner->isAlternate() &&
       m_disabledState != EnabledViaScript && m_owner->isInDocumentTree()) {
-    document().styleEngine().setPreferredStylesheetSetNameIfNotSet(
-        title, StyleEngine::DontUpdateActiveSheets);
+    document().styleEngine().setPreferredStylesheetSetNameIfNotSet(title);
   }
 
   bool mediaQueryMatches = true;
   LocalFrame* frame = loadingFrame();
   if (!m_owner->media().isEmpty() && frame) {
     MediaQuerySet* media = MediaQuerySet::create(m_owner->media());
     MediaQueryEvaluator evaluator(frame);
     mediaQueryMatches = evaluator.eval(media);
   }
 
@@ skipping 59 matching lines @@
           m_owner->relAttribute().getIconType());
     }
   }
 
   if (!m_owner->loadLink(type, as, media, m_owner->referrerPolicy(),
                          builder.url()))
     return;
 
   if (loadStylesheetIfNeeded(builder, type) == NotNeeded && 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->isConnected())
+      document().styleEngine().setNeedsActiveStyleUpdate(m_owner->treeScope());
   }
 }
 
-void LinkStyle::setSheetTitle(
-    const String& title,
-    StyleEngine::ActiveSheetsUpdate updateActiveSheets) {
+void LinkStyle::setSheetTitle(const String& title) {
   if (!m_owner->isInDocumentTree() || !m_owner->relAttribute().isStyleSheet())
     return;
 
   if (m_sheet)
     m_sheet->setTitle(title);
 
   if (title.isEmpty() || !isUnset() || m_owner->isAlternate())
     return;
 
   KURL href = m_owner->getNonEmptyURLAttribute(hrefAttr);
-  if (href.isValid() && !href.isEmpty()) {
-    document().styleEngine().setPreferredStylesheetSetNameIfNotSet(
-        title, updateActiveSheets);
-  }
+  if (href.isValid() && !href.isEmpty())
+    document().styleEngine().setPreferredStylesheetSetNameIfNotSet(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