Uses in-content styles for the tab crash page and adds an overlay to the favicon
for crashed tabs. Adds support for closing the crashed tab. The strings here
also refer to being able to restore all tabs, that will be implemented and
landed at the same time in bug 1109650 to avoid l10n churn.
Instead of attaching / listening for click events in BrowserOnClick for the
Try Again button, we instead bubble up an event when the Try Again button
is clicked. That event has a listener set up for it that is established during
delayedStartup, so it has a very high probability of being set. This bypasses
some error cases where we hadn't successfully attached BrowserOnClick in the past.
