Enforcing that custom tag extensions have correct super classes.

Source/bindings/dart/DartUtilities.cpp

Index: Source/bindings/dart/DartUtilities.cpp
diff --git a/Source/bindings/dart/DartUtilities.cpp b/Source/bindings/dart/DartUtilities.cpp
index 99508573306e3ed8719d254eee05ae6a70c5c86c..ad93749483e9e77df6f136b86b12423ca8462874 100644
--- a/Source/bindings/dart/DartUtilities.cpp
+++ b/Source/bindings/dart/DartUtilities.cpp
@@ -403,6 +403,21 @@ bool DartUtilities::isTypeSubclassOf(Dart_Handle type, intptr_t libraryId, const
     return boolResult;
 }
 
+bool DartUtilities::isTypeSubclassOfTag(Dart_Handle type, const String& tagName)
+{
+    Dart_Handle args[2] = { type, stringToDartString(tagName) };
+    Dart_Handle result = DartUtilities::invokeUtilsMethod("isTypeSubclassOfTag", 2, args);
+    ASSERT(!Dart_IsError(result));
+    if (Dart_IsError(result))

[vsm, 2013/10/14 18:25:33]

Move ASSERT into the if as ASSERT_NOT_REACHED?

[blois, 2013/10/14 19:24:13]

Done.

+        return false;
+
+    Dart_Handle exception = 0;
+    bool boolResult = dartToBool(result, exception);
+    if (exception)
+        return false;
+    return boolResult;
+}
+
 bool DartUtilities::isTypedData(Dart_Handle handle)
 {
     return (Dart_GetTypeOfTypedData(handle) != Dart_TypedData_kInvalid)