Avoid stack allocating StyleSheetCollections.

third_party/WebKit/Source/core/dom/TreeScopeStyleSheetCollection.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, 2010, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
@@ skipping 95 matching lines @@
         DCHECK(sheets[i]);
         if (sheets[i]->hasFontFaceRule()) {
             // FIXME: We don't need this for styles in shadow tree.
             sheets[i]->findFontFaceRules(fontFaceRules);
             hasFontFaceRule = true;
         }
     }
     return hasFontFaceRule;
 }
 
-void TreeScopeStyleSheetCollection::analyzeStyleSheetChange(StyleResolverUpdateMode updateMode, const StyleSheetCollection& newCollection, StyleSheetChange& change)
+void TreeScopeStyleSheetCollection::analyzeStyleSheetChange(StyleResolverUpdateMode updateMode, const HeapVector<Member<CSSStyleSheet>>& newActiveAuthorStyleSheets, StyleSheetChange& change)
 {
-    if (activeLoadingStyleSheetLoaded(newCollection.activeAuthorStyleSheets()))
+    if (activeLoadingStyleSheetLoaded(newActiveAuthorStyleSheets))
         return;
 
     if (updateMode != AnalyzedStyleUpdate)
         return;
 
     // Find out which stylesheets are new.
     HeapVector<Member<StyleSheetContents>> addedSheets;
-    if (m_activeAuthorStyleSheets.size() <= newCollection.activeAuthorStyleSheets().size()) {
-        change.styleResolverUpdateType = compareStyleSheets(m_activeAuthorStyleSheets, newCollection.activeAuthorStyleSheets(), addedSheets);
+    if (m_activeAuthorStyleSheets.size() <= newActiveAuthorStyleSheets.size()) {
+        change.styleResolverUpdateType = compareStyleSheets(m_activeAuthorStyleSheets, newActiveAuthorStyleSheets, addedSheets);
     } else {
-        StyleResolverUpdateType updateType = compareStyleSheets(newCollection.activeAuthorStyleSheets(), m_activeAuthorStyleSheets, addedSheets);
+        StyleResolverUpdateType updateType = compareStyleSheets(newActiveAuthorStyleSheets, m_activeAuthorStyleSheets, addedSheets);
         if (updateType != Additive) {
             change.styleResolverUpdateType = updateType;
         } else {
             change.styleResolverUpdateType = Reset;
             // If @font-face is removed, needs full style recalc.
             if (findFontFaceRulesFromStyleSheetContents(addedSheets, change.fontFaceRulesToRemove))
                 return;
         }
     }
 
@@ skipping 28 matching lines @@
 }
 
 DEFINE_TRACE(TreeScopeStyleSheetCollection)
 {
     visitor->trace(m_treeScope);
     visitor->trace(m_styleSheetCandidateNodes);
     StyleSheetCollection::trace(visitor);
 }
 
 } // namespace blink