NOT FOR COMMIT: test that interceptors work with the inspector.

test.js

+// Copyright 2017 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Run this test with
+// d8 test/mjsunit/mjsunit.js test/debugger/test-api.js --allow-natives-syntax --enable-inspector test.js
+
+let exception = null;
+let named_object = new NamedObject();
+
+function listener(event, exec_state, event_data, data) {
+  if (event != Debug.DebugEvent.Break) return;
+  try {
+    print(JSON.stringify(exec_state.frame().evaluate("named_object").value()));
+  } catch (e) {
+    exception = e;
+  }
+}
+
+let Debug = debug.Debug;
+Debug.setListener(listener);
+
+debugger;
+
+Debug.setListener(null);
+assertNull(exception);