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

Source/bindings/core/v8/V8Binding.h

 /*
 * Copyright (C) 2009 Google Inc. All rights reserved.
 * Copyright (C) 2012 Ericsson AB. 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.
@@ skipping 508 matching lines @@
 }
 
 inline v8::MaybeLocal<v8::Value> v8DateOrNaN(v8::Isolate* isolate, double value)
 {
     ASSERT(isolate);
     return v8::Date::New(isolate->GetCurrentContext(), std::isfinite(value) ? value : std::numeric_limits<double>::quiet_NaN());
 }
 
 // FIXME: Remove the special casing for NodeFilter and XPathNSResolver.
 PassRefPtrWillBeRawPtr<NodeFilter> toNodeFilter(v8::Handle<v8::Value>, v8::Handle<v8::Object>, ScriptState*);
-PassRefPtrWillBeRawPtr<XPathNSResolver> toXPathNSResolver(ScriptState*, v8::Handle<v8::Value>);
+XPathNSResolver* toXPathNSResolver(ScriptState*, v8::Handle<v8::Value>);
 
 bool toV8Sequence(v8::Handle<v8::Value>, uint32_t& length, v8::Isolate*, ExceptionState&);
 
 // Converts a JavaScript value to an array as per the Web IDL specification:
 // http://www.w3.org/TR/2012/CR-WebIDL-20120419/#es-array
 template <class T, class V8T>
 Vector<RefPtr<T>> toRefPtrNativeArrayUnchecked(v8::Local<v8::Value> v8Value, uint32_t length, v8::Isolate* isolate, ExceptionState& exceptionState)
 {
     Vector<RefPtr<T>> result;
     result.reserveInitialCapacity(length);
@@ skipping 459 matching lines @@
 PassRefPtr<TraceEvent::ConvertableToTraceFormat> devToolsTraceEventData(v8::Isolate*, ExecutionContext*, v8::Handle<v8::Function>);
 
 // Callback functions used by generated code.
 CORE_EXPORT void v8ConstructorAttributeGetter(v8::Local<v8::Name> propertyName, const v8::PropertyCallbackInfo<v8::Value>&);
 
 typedef void (*InstallTemplateFunction)(v8::Local<v8::FunctionTemplate>, v8::Isolate*);
 
 } // namespace blink
 
 #endif // V8Binding_h