Merge changes If1a62a90,Ibce79cf1,Ia2bbf01a,I1763be56,I56762747, ...

* changes:
  logd: don't send logs before the start time on the first flushTo()
  Revert "logd: drop mSequence from LogBufferElement"
  Revert "logd: regression in handling watermark boundary."
  Revert "logd: logcat --clear respect pruneMargin"
  logd: wait for timeout via CLOCK_MONOTONIC
  Revert "logd: wakeup wrap timeout if realtime changes drastically"
  logd: do not attempt to sort log messages by time