am 15e74b9d: Merge change 1939 into donut

Merge commit '15e74b9da8b4cda11ee54da1e77a02d1a86c944a'

* commit '15e74b9da8b4cda11ee54da1e77a02d1a86c944a':
  Temporarily suppress flaky test LocationManagerProximityTest until test harness support can be rolled out.
  Fix build breakage
  Revise the ImageButton class description to include information
  Record statistics about whether HTTP connections are reused.