Make setNeedsActiveStyleUpdate mark treescope dirty only.

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.
@@ skipping 167 matching lines @@
   // sync.
   DCHECK_GT(m_pendingScriptBlockingStylesheets, 0);
 
   m_pendingScriptBlockingStylesheets--;
   if (m_pendingScriptBlockingStylesheets)
     return;
 
   document().didRemoveAllPendingStylesheet();
 }
 
-void StyleEngine::setNeedsActiveStyleUpdate(
-    StyleSheet* sheet,
-    StyleResolverUpdateMode updateMode) {
-  // resolverChanged() is called for inactive non-master documents because
-  // import documents are inactive documents. resolverChanged() for imports
-  // will call resolverChanged() for the master document and update the active
-  // stylesheets including the ones from the import.
+void StyleEngine::setNeedsActiveStyleUpdate(TreeScope& treeScope) {
   if (!document().isActive() && isMaster())
     return;
 
-  if (sheet && document().isActive()) {
-    Node* node = sheet->ownerNode();
-    if (node && node->isConnected())
-      markTreeScopeDirty(node->treeScope());
-  }
-
-  resolverChanged(updateMode);
+  markTreeScopeDirty(treeScope);
 }
 
 void StyleEngine::addStyleSheetCandidateNode(Node& node) {
   if (!node.isConnected() || document().isDetached())
     return;
 
   DCHECK(!isXSLStyleSheet(node));
   TreeScope& treeScope = node.treeScope();
   TreeScopeStyleSheetCollection* collection =
       ensureStyleSheetCollectionFor(treeScope);
@@ skipping 349 matching lines @@
   if (m_resolver)
     m_resolver->invalidateMatchedPropertiesCache();
 }
 
 void StyleEngine::markTreeScopeDirty(TreeScope& scope) {
   if (scope == m_document) {
     markDocumentDirty();
     return;
   }
 
   DCHECK(m_styleSheetCollectionMap.contains(&scope));

[meade_UTC10, 2016/12/05 23:57:22]

It looks like this change is causing this DCHECK to be hit.

   m_dirtyTreeScopes.add(&scope);
   document().scheduleLayoutTreeUpdateIfNeeded();
 }
 
 void StyleEngine::markDocumentDirty() {
   m_documentScopeDirty = true;
   if (RuntimeEnabledFeatures::cssViewportEnabled())
     viewportRulesChanged();
   if (document().importLoader())
     document().importsController()->master()->styleEngine().markDocumentDirty();
@@ skipping 656 matching lines @@
 }
 
 DEFINE_TRACE_WRAPPERS(StyleEngine) {
   for (auto sheet : m_injectedAuthorStyleSheets) {
     visitor->traceWrappers(sheet);
   }
   visitor->traceWrappers(m_documentStyleSheetCollection);
 }
 
 }  // namespace blink