Add a runtime flag for XSLT

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 10 matching lines @@
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
 
 #include "config.h"
 #include "core/dom/DocumentStyleSheetCollection.h"
 
 #include "HTMLNames.h"
+#include "RuntimeEnabledFeatures.h"
 #include "SVGNames.h"
 #include "core/css/CSSStyleSheet.h"
 #include "core/css/resolver/StyleResolver.h"
 #include "core/dom/Document.h"
 #include "core/dom/Element.h"
 #include "core/dom/ProcessingInstruction.h"
 #include "core/dom/StyleEngine.h"
 #include "core/html/HTMLIFrameElement.h"
 #include "core/html/HTMLLinkElement.h"
 #include "core/html/HTMLStyleElement.h"
@@ skipping 19 matching lines @@
     DocumentOrderedList::iterator end = m_styleSheetCandidateNodes.end();
     for (DocumentOrderedList::iterator it = begin; it != end; ++it) {
         Node* n = *it;
         StyleSheet* sheet = 0;
         CSSStyleSheet* activeSheet = 0;
         if (n->nodeType() == Node::PROCESSING_INSTRUCTION_NODE && !document()->isHTMLDocument()) {
             // 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.
             ProcessingInstruction* pi = toProcessingInstruction(n);
             // Don't apply XSL transforms to already transformed documents -- <rdar://problem/4132806>
-            if (pi->isXSL() && !document()->transformSourceDocument()) {
+            if (RuntimeEnabledFeatures::xsltEnabled() && pi->isXSL() && !document()->transformSourceDocument()) {
                 // Don't apply XSL transforms until loading is finished.
                 if (!document()->parsing() && !pi->isLoading())
                     document()->applyXSLTransform(pi);
                 return;
             }
             sheet = pi->sheet();
             if (sheet && !sheet->disabled() && sheet->isCSSStyleSheet())
                 activeSheet = static_cast<CSSStyleSheet*>(sheet);
         } else if ((n->isHTMLElement() && (n->hasTagName(linkTag) || n->hasTagName(styleTag))) || (n->isSVGElement() && n->hasTagName(SVGNames::styleTag))) {
             Element* e = toElement(n);
@@ skipping 96 matching lines @@
     }
     m_scopingNodesForStyleScoped.didRemoveScopingNodes();
     m_activeAuthorStyleSheets.swap(activeCSSStyleSheets);
     m_styleSheetsForStyleSheetList.swap(styleSheets);
     updateUsesRemUnits();
 
     return requiresFullStyleRecalc;
 }
 
 }