= Summary =

It's now possible to write layout tests that exercise code in the UI process in iOS WebKit2. This allows testing of things like tapping, zooming, keyboard interaction, selection, text input etc.

This is done by running JavaScript in an isolated JS context in the UI process form a test. That JavaScript has access to a UIScriptController, which has properties that expose information about the state of the UI process,. and functions to make things happen, including event synthesis.

The UI script itself runs asynchronously, and many of the UIScriptController functions are asynchronous. Callbacks are used to tell the test when something completes.