Pass implementation object to supplemental classes by reference

Source/bindings/v8/custom/V8DocumentCustom.cpp

Index: Source/bindings/v8/custom/V8DocumentCustom.cpp
diff --git a/Source/bindings/v8/custom/V8DocumentCustom.cpp b/Source/bindings/v8/custom/V8DocumentCustom.cpp
index b12884cff3a2f3c723efb71aac3a4fd94890bda5..fb2bc2b92c33490c2c0f4eaf0076fd1f8aaf5c27 100644
--- a/Source/bindings/v8/custom/V8DocumentCustom.cpp
+++ b/Source/bindings/v8/custom/V8DocumentCustom.cpp
@@ -61,6 +61,7 @@ namespace WebCore {
 void V8Document::evaluateMethodCustom(const v8::FunctionCallbackInfo<v8::Value>& info)
 {
     RefPtr<Document> document = V8Document::toNative(info.Holder());
+    ASSERT(document);
     ExceptionState exceptionState(ExceptionState::ExecutionContext, "evaluate", "Document", info.Holder(), info.GetIsolate());
     V8TRYCATCH_FOR_V8STRINGRESOURCE_VOID(V8StringResource<>, expression, info[0]);
     RefPtr<Node> contextNode;
@@ -80,7 +81,7 @@ void V8Document::evaluateMethodCustom(const v8::FunctionCallbackInfo<v8::Value>&
     if (V8XPathResult::hasInstance(info[4], info.GetIsolate()))
         inResult = V8XPathResult::toNative(v8::Handle<v8::Object>::Cast(info[4]));
 
-    V8TRYCATCH_VOID(RefPtr<XPathResult>, result, DocumentXPathEvaluator::evaluate(document.get(), expression, contextNode.get(), resolver.release(), type, inResult.get(), exceptionState));
+    V8TRYCATCH_VOID(RefPtr<XPathResult>, result, DocumentXPathEvaluator::evaluate(*document, expression, contextNode.get(), resolver.release(), type, inResult.get(), exceptionState));
     if (exceptionState.throwIfNeeded())
         return;