Cleanup dart to string conversions.

Source/WebCore/bindings/dart/custom/DartWebSocketCustom.cpp

Index: Source/WebCore/bindings/dart/custom/DartWebSocketCustom.cpp
diff --git a/Source/WebCore/bindings/dart/custom/DartWebSocketCustom.cpp b/Source/WebCore/bindings/dart/custom/DartWebSocketCustom.cpp
index 2a34bb5629755ddebd10ed1a66dcc1a28246a6c4..de4ac2d4d933df1aeb477f2d80c5016357c6a3f8 100644
--- a/Source/WebCore/bindings/dart/custom/DartWebSocketCustom.cpp
+++ b/Source/WebCore/bindings/dart/custom/DartWebSocketCustom.cpp
@@ -52,11 +52,9 @@ void constructorCallback(Dart_NativeArguments args)
             goto fail;
         }
 
-        const ParameterAdapter<String> url(Dart_GetNativeArgument(args, 0));
-        if (!url.conversionSuccessful()) {
-            exception = url.exception();
+        DartStringAdapter url = DartUtilities::dartToString(Dart_GetNativeArgument(args, 0), exception);
+        if (exception)
             goto fail;
-        }
 
         const KURL& absoluteURL = context->completeURL(url);
 
@@ -99,11 +97,9 @@ void sendCallback(Dart_NativeArguments args)
                 goto fail;
             result = receiver->send(data, ec);
         } else if (Dart_IsString(dataHandle)) {
-            const ParameterAdapter<String> data(dataHandle);
-            if (!data.conversionSuccessful()) {
-                exception = data.exception();
+            DartStringAdapter data = DartUtilities::dartToString(dataHandle, exception);
+            if (exception)
                 goto fail;
-            }
             result = receiver->send(data, ec);
         } else {
             exception = Dart_NewString("Unsupported data argument type");