Add synchronization to DeferredBindRunnables

Seems that on occasion the list is being iterated on while being
modified.  To fix this added synchronization to all modifications
to the list as well as iterating on a copy of the list to cut
down on time holding the lock.

Bug: 12885709
Change-Id: I4287bdedbeb8e438b49c1f79b44819a752c28a69