Original commit message from CVS:
* libs/gst/base/gstbasesink.c: (gst_base_sink_loop):
Improve debugging.
* libs/gst/base/gstbasesrc.c: (gst_base_src_query_latency),
(gst_base_src_default_query), (gst_base_src_wait),
(gst_base_src_do_sync), (gst_base_src_change_state):
Rearrange some code so that we can add support for measuring the
startup latency.