API functions returning Promises should not throw exceptions.

Source/core/testing/Internals.idl

Index: Source/core/testing/Internals.idl
diff --git a/Source/core/testing/Internals.idl b/Source/core/testing/Internals.idl
index 7879a1adc3b799aca50ee9a3546cb43f905343e3..15c1cabddd00a4acc476315b1fa9a890f24e9c75 100644
--- a/Source/core/testing/Internals.idl
+++ b/Source/core/testing/Internals.idl
@@ -283,6 +283,9 @@
     [CallWith=ExecutionContext] Promise createResolvedPromise(any value);
     [CallWith=ExecutionContext] Promise createRejectedPromise(any reason);
     [CallWith=ExecutionContext] Promise addOneToPromise(Promise promise);
+    [CallWith=ExecutionContext, RaisesException] Promise promiseCheck(long arg1, boolean arg2, Dictionary arg3, DOMString arg4);
+    [CallWith=ExecutionContext] Promise promiseCheckWithoutExceptionState(Dictionary arg1, DOMString arg2, DOMString... variadic);
+    [CallWith=ExecutionContext] Promise promiseCheckRange([EnforceRange] octet arg1);
 
     void startSpeechInput(Element element);
     void setValueForUser(Element element, DOMString value);