Fix FormData overloaded append.

Source/bindings/dart/custom/DartFormDataCustom.cpp

 // Copyright 2011, 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 45 matching lines @@
     Dart_ThrowException(exception);
     ASSERT_NOT_REACHED();
 }
 
 void appendCallback(Dart_NativeArguments args)
 {
     Dart_Handle exception = 0;
     {
         DOMFormData* receiver = DartDOMWrapper::receiver<DOMFormData>(args);
 
-        DartStringAdapter name = DartUtilities::dartToStringWithNullCheck(args, 1, exception);
+        DartStringAdapter name = DartUtilities::dartToString(args, 1, exception);
         if (exception)
             goto fail;
 
-        DartStringAdapter value = DartUtilities::dartToStringWithNullCheck(args, 2, exception);
+        Dart_Handle arg2 = Dart_GetNativeArgument(args, 2);
+
+        if (Dart_IsString(arg2)) {
+            ASSERT(Dart_GetNativeArgumentCount(args) == 3);
+
+            DartStringAdapter value = DartUtilities::dartToString(arg2, exception);
+            if (exception)
+                goto fail;
+
+            receiver->append(name, value);
+            return;
+        }
+
+        Blob* blob = DartBlob::toNative(arg2, exception);
         if (exception)
             goto fail;
 
-        receiver->append(name, value);
-
-        return;
-    }
-
-fail:
-    Dart_ThrowException(exception);
-    ASSERT_NOT_REACHED();
-}
-
-void appendBlobCallback(Dart_NativeArguments args)
-{
-    Dart_Handle exception = 0;
-    {
-        DOMFormData* receiver = DartDOMWrapper::receiver<DOMFormData>(args);
-
-        DartStringAdapter name = DartUtilities::dartToStringWithNullCheck(args, 1, exception);
-        if (exception)
-            goto fail;
-
-        Dart_Handle valueHandle = Dart_GetNativeArgument(args, 2);
-        Blob* blob = DartBlob::toNative(valueHandle, exception);
-        if (exception)
-            goto fail;
+        if (Dart_GetNativeArgumentCount(args) == 3) {
+            receiver->append(name, blob);
+            return;
+        }
 
         DartStringAdapter filename = DartUtilities::dartToStringWithNullCheck(args, 3, exception);
         if (exception)
             goto fail;
 
         receiver->append(name, blob, filename);
-
         return;
     }
 
 fail:
     Dart_ThrowException(exception);
     ASSERT_NOT_REACHED();
 }
 
 }
 
 }