Oilpan: Prepare to move HTMLResourcePreloader to Oilpan heap.

Source/core/html/parser/HTMLDocumentParser.cpp

Index: Source/core/html/parser/HTMLDocumentParser.cpp
diff --git a/Source/core/html/parser/HTMLDocumentParser.cpp b/Source/core/html/parser/HTMLDocumentParser.cpp
index a6754446ced184a60f8c79547c3c16dbdab6ab5f..79ed79a9dbb7cf9862475db6147d07bc363c9ec5 100644
--- a/Source/core/html/parser/HTMLDocumentParser.cpp
+++ b/Source/core/html/parser/HTMLDocumentParser.cpp
@@ -112,7 +112,7 @@ HTMLDocumentParser::HTMLDocumentParser(HTMLDocument& document, bool reportErrors
     , m_parserScheduler(HTMLParserScheduler::create(this))
     , m_xssAuditorDelegate(&document)
     , m_weakFactory(this)
-    , m_preloader(adoptPtr(new HTMLResourcePreloader(&document)))
+    , m_preloader(HTMLResourcePreloader::create(document))
     , m_isPinnedToMainThread(false)
     , m_endWasDelayed(false)
     , m_haveBackgroundParser(false)
@@ -166,6 +166,7 @@ void HTMLDocumentParser::trace(Visitor* visitor)
     visitor->trace(m_treeBuilder);
     visitor->trace(m_xssAuditorDelegate);
     visitor->trace(m_scriptRunner);
+    visitor->trace(m_preloader);
     ScriptableDocumentParser::trace(visitor);
     HTMLScriptRunnerHost::trace(visitor);
 }