Revert 241162 "Make clicking the restart bubble for crashed apps..."

Revert 241162 "Make clicking the restart bubble for crashed apps..."

This CL had the unintended side effect that Simulate Browser Restart no longer
works. Also, experimentation suggests that the original bug it was intended to
fix works without this change now.

> Make clicking the restart bubble for crashed apps work.
> 
> Previously AppLoadService listened for
> NOTIFICATION_EXTENSION_HOST_DID_STOP_LOADING before dispatching the
> onRestarted() event after a reload, but in the case of packaged apps, which use
> non-persistent background pages, that notification will never get fired. This
> is because reloading an app doesn't cause its background page to get loaded -
> only a relevant event causes the page to be woken up.
> 
> This patch fixes the issue by listening for NOTIFICATION_EXTENSION_LOADED
> instead, which is always fired after a reload. It also determines whether an
> extension is listening to an event by checking which events it has registered
> for, not which ones it currently has a listener for,
> NOTIFICATION_EXTENSION_LOADED is the notification that listeners get created
> on, and so to avoid raciness we check registered events (ie: the persisted
> list of events that an extension is interested in).
> 
> BUG=327964
> 
> Review URL: https://codereview.chromium.org/93593003

TBR=koz@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=243703

[koz (OOO until 15th September), 2014-01-09 00:03:40]

Committed patchset #1 manually as r243703.