73570db59f
Instead of a runs-forever periodic alarm that drives key/value backup passes, we instead schedule-on-demand a trigger job that will kick off the pass after a batching interval. The key semantic change is that we now never wake for key/value backup work unless we've been explicitly asked to do so. We also use a rather longer batching interval than was previously the case. Bug 19536032 Change-Id: Ie377562b2812c9aeda0ee73770dfa94af6017778