atspi: use detail value of window activated signal

atspi: use detail value of window activated signal

The detail value of window activated signal is using for following cases

(1) support "default_label" attribute of window
(2) notify existing keyboard window.
The keyboard window would exist always, once it shows.
So if screen-reader turns off, and turn on again, there was no ATSPI signal.
We are using 'activate' signal for this case to get the reference of
keyboard window. And we are using detail value to reduce a call of IPC.
orig: ba47f6bba8065c4ae1f4fd20e8d60ff1487be2b1

Change-Id: I36c5b96868233bdf7a162f4a1d23057ed9b2a05f
Signed-off-by: Shilpa Singh <shilpa.singh@samsung.com>