Oilpan: have xml/ objects on the heap by default.

Source/bindings/core/v8/custom/V8CustomXPathNSResolver.cpp

 // Copyright (c) 2008, Google Inc.
 // All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 // notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
@@ skipping 25 matching lines @@
 #include "core/frame/FrameConsole.h"
 #include "core/frame/FrameHost.h"
 #include "core/frame/LocalDOMWindow.h"
 #include "core/frame/LocalFrame.h"
 #include "core/inspector/ConsoleMessage.h"
 #include "core/inspector/ScriptCallStack.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
 
-PassRefPtrWillBeRawPtr<V8CustomXPathNSResolver> V8CustomXPathNSResolver::create(ScriptState* scriptState, v8::Local<v8::Object> resolver)
+V8CustomXPathNSResolver* V8CustomXPathNSResolver::create(ScriptState* scriptState, v8::Local<v8::Object> resolver)
 {
-    return adoptRefWillBeNoop(new V8CustomXPathNSResolver(scriptState, resolver));
+    return new V8CustomXPathNSResolver(scriptState, resolver);
 }
 
 V8CustomXPathNSResolver::V8CustomXPathNSResolver(ScriptState* scriptState, v8::Local<v8::Object> resolver)
     : m_scriptState(scriptState)
     , m_resolver(resolver)
 {
 }
 
 AtomicString V8CustomXPathNSResolver::lookupNamespaceURI(const String& prefix)
 {
@@ skipping 31 matching lines @@
     TOSTRING_DEFAULT(V8StringResource<TreatNullAsNullString>, returnString, retval, nullAtom);
     return returnString;
 }
 
 DEFINE_TRACE(V8CustomXPathNSResolver)
 {
     XPathNSResolver::trace(visitor);
 }
 
 } // namespace blink