Add a feature that reports sites as slow or data heavy that sends a report to Chrome and to the web site owner. Because it's a user driven action, we can maybe report more data similar to how we do for crashes.

This could be used in a number of ways:
1. A general report slow button
2. When we detect a site is doing a bad thing (too much CPU, too much data) we can show the user an option to pause the site and/or report it as slow.
3. ...?