Added addXSLStyleSheet and removeXSLStyleSheet to StyleEngine.

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 33 matching lines @@
 }
 
 void DocumentStyleSheetCollection::collectStyleSheetsFromCandidates(StyleEngine* engine, DocumentStyleSheetCollector& collector)
 {
     DocumentOrderedList::iterator begin = m_styleSheetCandidateNodes.begin();
     DocumentOrderedList::iterator end = m_styleSheetCandidateNodes.end();
     for (DocumentOrderedList::iterator it = begin; it != end; ++it) {
         Node* n = *it;
         StyleSheetCandidate candidate(*n);
 
-        if (candidate.isXSL()) {
-            // Processing instruction (XML documents only).
-            // We don't support linking to embedded CSS stylesheets, see <https://bugs.webkit.org/show_bug.cgi?id=49281> for discussion.
-            // Don't apply XSL transforms to already transformed documents -- <rdar://problem/4132806>
-            if (RuntimeEnabledFeatures::xsltEnabled() && !document().transformSourceDocument()) {
-                ProcessingInstruction* pi = toProcessingInstruction(n);
-                // Don't apply XSL transforms until loading is finished.
-                if (!document().parsing() && !pi->isLoading())
-                    document().applyXSLTransform(pi);
-                return;
-            }
-
-            continue;
-        }
-
+        ASSERT(!candidate.isXSL());
         if (candidate.isImport()) {
             Document* document = candidate.importedDocument();
             if (!document)
                 continue;
             if (collector.hasVisited(document))
                 continue;
             collector.willVisit(document);
             document->styleEngine()->updateStyleSheetsInImport(collector);
             continue;
         }
@@ skipping 56 matching lines @@
     m_scopingNodesForStyleScoped.didRemoveScopingNodes();
 
     collection.swap(*this);
 
     updateUsesRemUnits();
 
     return change.requiresFullStyleRecalc;
 }
 
 }