Oilpan: make DocumentFragment a heap allocated object.

Source/core/html/track/vtt/VTTParser.cpp

Index: Source/core/html/track/vtt/VTTParser.cpp
diff --git a/Source/core/html/track/vtt/VTTParser.cpp b/Source/core/html/track/vtt/VTTParser.cpp
index 5c98ee48cc7c7f4f0c7f8dde4de021ddde2bb07e..1268d77b1a5942c08129a97bbcc686e11ee9dc73 100644
--- a/Source/core/html/track/vtt/VTTParser.cpp
+++ b/Source/core/html/track/vtt/VTTParser.cpp
@@ -321,7 +321,7 @@ public:
     VTTTreeBuilder(Document& document)
         : m_document(document) { }
 
-    PassRefPtr<DocumentFragment> buildFromString(const String& cueText);
+    PassRefPtrWillBeRawPtr<DocumentFragment> buildFromString(const String& cueText);
 
 private:
     void constructTreeFromToken(Document&);
@@ -332,13 +332,13 @@ private:
     Document& m_document;
 };
 
-PassRefPtr<DocumentFragment> VTTTreeBuilder::buildFromString(const String& cueText)
+PassRefPtrWillBeRawPtr<DocumentFragment> VTTTreeBuilder::buildFromString(const String& cueText)
 {
     // Cue text processing based on
     // 5.4 WebVTT cue text parsing rules, and
     // 5.5 WebVTT cue text DOM construction rules
 
-    RefPtr<DocumentFragment> fragment = DocumentFragment::create(m_document);
+    RefPtrWillBeRawPtr<DocumentFragment> fragment = DocumentFragment::create(m_document);
 
     if (cueText.isEmpty()) {
         fragment->parserAppendChild(Text::create(m_document, ""));
@@ -356,7 +356,7 @@ PassRefPtr<DocumentFragment> VTTTreeBuilder::buildFromString(const String& cueTe
     return fragment.release();
 }
 
-PassRefPtr<DocumentFragment> VTTParser::createDocumentFragmentFromCueText(Document& document, const String& cueText)
+PassRefPtrWillBeRawPtr<DocumentFragment> VTTParser::createDocumentFragmentFromCueText(Document& document, const String& cueText)
 {
     VTTTreeBuilder treeBuilder(document);
     return treeBuilder.buildFromString(cueText);