Both unittests and Earl Grey tests currently rely on examining the DOM document's content in order to validate feature functionality. (For example, |getBoundingRectOfElement()| used in Context Menu tests.)

Due to the separation of frame content inside a webpage, the tests currently can only validate features inside the main frame.

The test helpers should be extended to be able to validate content inside any frame. (One possibility is to inject JavaScript in test targets only which can concatenate all frame content and then return it to the native app.)