CSS: Checked downcast for ShadowTreeStyleSheetCollection

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.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) Research In Motion Limited 2010-2011. All rights reserved.
@@ skipping 228 matching lines @@
 
 bool StyleEngine::shouldUpdateShadowTreeStyleSheetCollection(StyleResolverUpdateMode updateMode) const
 {
     return !m_dirtyTreeScopes.isEmpty() || updateMode == FullStyleUpdate;
 }
 
 void StyleEngine::clearMediaQueryRuleSetOnTreeScopeStyleSheets(UnorderedTreeScopeSet& treeScopes)
 {
     for (TreeScope* treeScope : treeScopes) {
         DCHECK(treeScope != m_document);
-        ShadowTreeStyleSheetCollection* collection = static_cast<ShadowTreeStyleSheetCollection*>(styleSheetCollectionFor(*treeScope));
+        ShadowTreeStyleSheetCollection* collection = toShadowTreeStyleSheetCollection(styleSheetCollectionFor(*treeScope));
         DCHECK(collection);
         collection->clearMediaQueryRuleSetStyleSheets();
     }
 }
 
 void StyleEngine::clearMediaQueryRuleSetStyleSheets()
 {
     resolverChanged(FullStyleUpdate);
     documentStyleSheetCollection()->clearMediaQueryRuleSetStyleSheets();
     clearMediaQueryRuleSetOnTreeScopeStyleSheets(m_activeTreeScopes);
 }
 
 void StyleEngine::updateStyleSheetsInImport(DocumentStyleSheetCollector& parentCollector)
 {
     DCHECK(!isMaster());
     HeapVector<Member<StyleSheet>> sheetsForList;
     ImportedDocumentStyleSheetCollector subcollector(parentCollector, sheetsForList);
     documentStyleSheetCollection()->collectStyleSheets(*this, subcollector);
     documentStyleSheetCollection()->swapSheetsForSheetList(sheetsForList);
 }
 
 void StyleEngine::updateActiveStyleSheetsInShadow(StyleResolverUpdateMode updateMode, TreeScope* treeScope, UnorderedTreeScopeSet& treeScopesRemoved)
 {
     DCHECK_NE(treeScope, m_document);
-    ShadowTreeStyleSheetCollection* collection = static_cast<ShadowTreeStyleSheetCollection*>(styleSheetCollectionFor(*treeScope));
+    ShadowTreeStyleSheetCollection* collection = toShadowTreeStyleSheetCollection(styleSheetCollectionFor(*treeScope));
     DCHECK(collection);
     collection->updateActiveStyleSheets(*this, updateMode);
     if (!collection->hasStyleSheetCandidateNodes()) {
         treeScopesRemoved.add(treeScope);
         // When removing TreeScope from ActiveTreeScopes,
         // its resolver should be destroyed by invoking resetAuthorStyle.
         DCHECK(!treeScope->scopedStyleResolver());
     }
 }
 
@@ skipping 474 matching lines @@
     visitor->trace(m_styleInvalidator);
     visitor->trace(m_dirtyTreeScopes);
     visitor->trace(m_activeTreeScopes);
     visitor->trace(m_fontSelector);
     visitor->trace(m_textToSheetCache);
     visitor->trace(m_sheetToTextCache);
     CSSFontSelectorClient::trace(visitor);
 }
 
 } // namespace blink