Move preferred stylesheet logic into StyleEngine.

third_party/WebKit/Source/core/dom/DocumentStyleSheetCollection.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 44 matching lines @@
                 continue;
             if (collector.hasVisited(document))
                 continue;
             collector.willVisit(document);
             document->styleEngine().updateStyleSheetsInImport(collector);
             continue;
         }
 
         if (candidate.isEnabledAndLoading()) {
             // it is loading but we should still decide which style sheet set to use
-            if (candidate.hasPreferrableName(engine.preferredStylesheetSetName()))
-                engine.selectStylesheetSetName(candidate.title());
+            if (candidate.hasPreferrableName())
+                engine.setPreferredStylesheetSetNameIfNotSet(candidate.title());
             continue;
         }
 
         StyleSheet* sheet = candidate.sheet();
         if (!sheet)
             continue;
 
-        if (candidate.hasPreferrableName(engine.preferredStylesheetSetName()))
-            engine.selectStylesheetSetName(candidate.title());
+        if (candidate.hasPreferrableName())
+            engine.setPreferredStylesheetSetNameIfNotSet(candidate.title());
         collector.appendSheetForList(sheet);
         if (candidate.canBeActivated(engine.preferredStylesheetSetName()))
             collector.appendActiveStyleSheet(toCSSStyleSheet(sheet));
     }
 }
 
 void DocumentStyleSheetCollection::collectStyleSheets(StyleEngine& engine, DocumentStyleSheetCollector& collector)
 {
     ASSERT(&document().styleEngine() == &engine);
     collector.appendActiveStyleSheets(engine.injectedAuthorStyleSheets());
@@ skipping 28 matching lines @@
             styleResolver->lazyAppendAuthorStyleSheets(m_activeAuthorStyleSheets.size(), collection.activeAuthorStyleSheets());
         }
     }
     if (change.requiresFullStyleRecalc)
         document().setNeedsStyleRecalc(SubtreeStyleChange, StyleChangeReasonForTracing::create(StyleChangeReason::ActiveStylesheetsUpdate));
 
     collection.swap(*this);
 }
 
 } // namespace blink