Trace StyleEngine::clearResolver

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.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) Research In Motion Limited 2010-2011. All rights reserved.
@@ skipping 376 matching lines @@
     m_resolver->appendAuthorStyleSheets(documentStyleSheetCollection()->activeAuthorStyleSheets());
     for (TreeScope* treeScope : m_activeTreeScopes) {
         if (TreeScopeStyleSheetCollection* collection = m_styleSheetCollectionMap.get(treeScope))
             m_resolver->appendAuthorStyleSheets(collection->activeAuthorStyleSheets());
     }
     m_resolver->finishAppendAuthorStyleSheets();
 }
 
 void StyleEngine::createResolver()
 {
-    TRACE_EVENT0("blink", "StyleEngine::createResolver");
+    TRACE_EVENT1("blink", "StyleEngine::createResolver", "frame", document().frame());
     // It is a programming error to attempt to resolve style on a Document
     // which is not in a frame. Code which hits this should have checked
     // Document::isActive() before calling into code which could get here.
 
     ASSERT(document().frame());
 
     m_resolver = adoptPtrWillBeNoop(new StyleResolver(*m_document));
 
     // A scoped style resolver for document will be created during
     // appendActiveAuthorStyleSheets if needed.
@@ skipping 10 matching lines @@
     // StyleEngine::shadowRootRemovedFromDocument removes not-in-document
     // treescopes from activeTreeScopes. StyleEngine::didRemoveShadowRoot
     // removes treescopes which are being destroyed from activeTreeScopes.
     // So we need to clearScopedStyleResolver for treescopes which have been
     // just removed from document. If document is destroyed before invoking
     // updateActiveStyleSheets, the treescope has a scopedStyleResolver which
     // has destroyed StyleSheetContents.
     for (TreeScope* treeScope : m_activeTreeScopes)
         treeScope->clearScopedStyleResolver();
 
-    m_resolver.clear();
+    if (m_resolver) {
+        TRACE_EVENT1("blink", "StyleEngine::clearResolver", "frame", document().frame());
+        m_resolver.clear();
+    }
 }
 
 void StyleEngine::clearMasterResolver()
 {
     if (Document* master = this->master())
         master->styleEngine().clearResolver();
 }
 
 unsigned StyleEngine::resolverAccessCount() const
 {
@@ skipping 284 matching lines @@
     visitor->trace(m_dirtyTreeScopes);
     visitor->trace(m_activeTreeScopes);
     visitor->trace(m_fontSelector);
     visitor->trace(m_textToSheetCache);
     visitor->trace(m_sheetToTextCache);
 #endif
     CSSFontSelectorClient::trace(visitor);
 }
 
 }