Some callers of the keyring prompt keep the dialog up while
processing the prompt. Allow the user to cancel the prompt
while in this state.
This is propagated to the caller, who can cancel the operation
in question when this occurs.
https://bugzilla.gnome.org/show_bug.cgi?id=682830
* Prompters have state, and cancelling an already prompter will
cause prompts that are in progress to fail.
* In addition allow replacement of our shell prompter for debugging
purposes.
https://bugzilla.gnome.org/show_bug.cgi?id=695485
Components are pieces of the shell code that can be added/removed
at runtime, like extension, but are tied more directly to a session
mode. The session polkit agent, the network agent, autorun/automount,
are all components, keyring, recorder and telepathy client are all
now copmonents.
https://bugzilla.gnome.org/show_bug.cgi?id=683156