Get rid of last uses of deprecated toWebCoreString(v8::Handle<v8::Value>)

Source/bindings/v8/V8Initializer.cpp

Index: Source/bindings/v8/V8Initializer.cpp
diff --git a/Source/bindings/v8/V8Initializer.cpp b/Source/bindings/v8/V8Initializer.cpp
index 4a93013ac8782a628472d93cd32400c1db953be5..a7bcf8b8b817e64e65c6a7953cd4df42f28420c8 100644
--- a/Source/bindings/v8/V8Initializer.cpp
+++ b/Source/bindings/v8/V8Initializer.cpp
@@ -200,7 +200,8 @@ static void messageHandlerInWorker(v8::Handle<v8::Message> message, v8::Handle<v
     // During the frame teardown, there may not be a valid context.
     if (ExecutionContext* context = getExecutionContext()) {
         String errorMessage = toWebCoreString(message->Get());
-        String sourceURL = toWebCoreString(message->GetScriptResourceName());
+        V8TRYCATCH_FOR_V8STRINGRESOURCE_VOID(V8StringResource<>, sourceURL, message->GetScriptResourceName());
+
         RefPtr<ErrorEvent> event = ErrorEvent::create(errorMessage, sourceURL, message->GetLineNumber(), message->GetStartColumn() + 1, DOMWrapperWorld::current());
         AccessControlStatus corsStatus = message->IsSharedCrossOrigin() ? SharableCrossOrigin : NotSharableCrossOrigin;