[EasyUnlock] Observe proximity changes and clean up TX power strategy.

components/proximity_auth/proximity_monitor_impl.cc

Index: components/proximity_auth/proximity_monitor_impl.cc
diff --git a/components/proximity_auth/proximity_monitor_impl.cc b/components/proximity_auth/proximity_monitor_impl.cc
index 22bedf43eb816f15e66009457e7a66afa588b5cc..0b63695ac3b8886fffae1311e6fc9fe4132402e7 100644
--- a/components/proximity_auth/proximity_monitor_impl.cc
+++ b/components/proximity_auth/proximity_monitor_impl.cc
@@ -27,7 +27,7 @@ const int kPollingTimeoutMs = 250;
 
 // The RSSI threshold below which we consider the remote device to not be in
 // proximity.

[sacomoto, 2017/05/22 07:30:29]

Please add to the comment the pair of devices this value works well (i.e. that
you test with). 

[Tim Song, 2017/05/22 17:50:59]

Done.

-const int kRssiThreshold = -45;
+const int kRssiThreshold = -50;
 
 // The weight of the most recent RSSI sample.
 const double kRssiSampleWeight = 0.3;