Schedule layout tree update for dirty tree scopes.

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 555 matching lines @@
 }
 
 void StyleEngine::markTreeScopeDirty(TreeScope& scope) {
   if (scope == m_document) {
     markDocumentDirty();
     return;
   }
 
   DCHECK(m_styleSheetCollectionMap.contains(&scope));
   m_dirtyTreeScopes.add(&scope);
+  document().scheduleLayoutTreeUpdateIfNeeded();
 }
 
 void StyleEngine::markDocumentDirty() {
   m_documentScopeDirty = true;
   if (RuntimeEnabledFeatures::cssViewportEnabled())
     viewportRulesChanged();
   if (document().importLoader())
     document().importsController()->master()->styleEngine().markDocumentDirty();
+  else
+    document().scheduleLayoutTreeUpdateIfNeeded();
 }
 
 CSSStyleSheet* StyleEngine::createSheet(Element& element,
                                         const String& text,
                                         TextPosition startPosition,
                                         StyleEngineContext& context) {
   DCHECK(element.document() == document());
   CSSStyleSheet* styleSheet = nullptr;
 
   addPendingSheet(context);
@@ skipping 644 matching lines @@
 }
 
 DEFINE_TRACE_WRAPPERS(StyleEngine) {
   for (auto sheet : m_injectedAuthorStyleSheets) {
     visitor->traceWrappers(sheet);
   }
   visitor->traceWrappers(m_documentStyleSheetCollection);
 }
 
 }  // namespace blink