Add libgui bq_consumer_attach_callback flag

Add a flag for enabling IProducerListener callback when the consumer
attaches a buffer.

Bug: 353202582
Flag: EXEMPT adding flag
Test: n/a
Merged-In: I3268cb82fdc7d194f8b1864b8a72147ff51e3973
Merged-In: Ieaa25ed05d04a33de47de7ee3296e4bf1dde7a26
Change-Id: Ieaa25ed05d04a33de47de7ee3296e4bf1dde7a26
1 file changed