Improve Dart Debugger performance and robustness by creating Dart wrappers using the standard SetNa…

Source/bindings/dart/DartDOMWrapper.h

Index: Source/bindings/dart/DartDOMWrapper.h
diff --git a/Source/bindings/dart/DartDOMWrapper.h b/Source/bindings/dart/DartDOMWrapper.h
index a7c6cc080495f19a290c9d088f4ec70b7a0c28a0..5b2b058805e0f424aa0535b648169ff4f7f1cf2c 100644
--- a/Source/bindings/dart/DartDOMWrapper.h
+++ b/Source/bindings/dart/DartDOMWrapper.h
@@ -188,8 +188,8 @@ private:
     {
         intptr_t value;
         Dart_Handle result = Dart_GetNativeInstanceField(wrapper, index, &value);
-        ASSERT(!Dart_IsError(result));
-        UNUSED_PARAM(result);
+        if (Dart_IsError(result))
+            return 0;
         return reinterpret_cast<void*>(value);
     }