WiFiMetrics: Add LastResortWatchdog success metric

Added a metric that tracks how often WifiLastResortWatchdog triggers
successfully fix wifi, allowing wifi to connect to a network after
triggering. It does not count a success, if the connection occurs
after a new network becomes available.

BUG=30407550
TEST=Unit Tests

Change-Id: I68d1f003fee9eb8074c04db141bd7b5c3089d57b
5 files changed
tree: eef902512f84616e429816f55cd364ed24673ff0
  1. service/
  2. tests/