New Additions to WifiScanner APIs [DO NOT MERGE]

Added single shot scan, and maxScansToCache. Also fixed getScanResults()
to report scan results to listeners.

Bug: 18087596
Bug: 17694040
Bug: 18059273

Change-Id: Id623ab9ee2ab89c86a35082279331fa609016347
8 files changed
tree: b3c0a41432f6de54a4d63109e16ca7e1a8b86eb6
  1. service/