Proximity Auth: Remove unused metrics loggers.

R=khorimoto@chromium.org

Bug: 899324
Test: none
Change-Id: I0c579f604635d89ba2b1394d5142fbb21de12560
Reviewed-on: https://chromium-review.googlesource.com/c/1330828Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Reviewed-by: Steven Holte <holte@chromium.org>
Commit-Queue: James Hawkins <jhawkins@chromium.org>
Cr-Commit-Position: refs/heads/master@{#608148}

chromeos/components/proximity_auth/metrics.cc

@@ -56,20 +56,6 @@ void RecordAuthProximityRollingRssi(int rolling_rssi) {
                            rolling_rssi);
 }
 
-void RecordAuthProximityTransmitPowerDelta(int transmit_power_delta) {
-  if (transmit_power_delta != kUnknownProximityValue)
-    transmit_power_delta = std::min(50, std::max(-100, transmit_power_delta));
-
-  base::UmaHistogramSparse("EasyUnlock.AuthProximity.TransmitPowerDelta",
-                           transmit_power_delta);
-}
-
-void RecordAuthProximityTimeSinceLastZeroRssi(
-    base::TimeDelta time_since_last_zero_rssi) {
-  UMA_HISTOGRAM_TIMES("EasyUnlock.AuthProximity.TimeSinceLastZeroRssi",
-                      time_since_last_zero_rssi);
-}
-
 void RecordAuthProximityRemoteDeviceModelHash(const std::string& device_model) {
   base::UmaHistogramSparse("EasyUnlock.AuthProximity.RemoteDeviceModelHash",
                            HashDeviceModelName(device_model));

chromeos/components/proximity_auth/metrics.h

@@ -31,16 +31,6 @@ enum class RemoteSecuritySettingsState {
 // are available.
 void RecordAuthProximityRollingRssi(int rolling_rssi);
 
-// Records the difference between the transmit power and maximum transmit power,
-// upon a successful auth attempt. |transmit_power_delta| should be set to
-// |kUnknownProximityValue| if no Tx power readings are available.
-void RecordAuthProximityTransmitPowerDelta(int transmit_power_delta);
-
-// Records the time elapsed since the last zero RSSI value was read, upon a
-// successful auth attempt.
-void RecordAuthProximityTimeSinceLastZeroRssi(
-    base::TimeDelta time_since_last_zero_rssi);
-
 // Records the phone model used for a successful auth attempt. The model is
 // recorded as a 32-bit hash due to the limits of UMA. |device_model| should be
 // set to |kUnknownDeviceModel| if the device model could not be read.

tools/metrics/histograms/histograms.xml

@@ -24922,6 +24922,9 @@ uploading your change for review.
 </histogram>
 
 <histogram name="EasyUnlock.AuthProximity.TimeSinceLastZeroRssi" units="ms">
+  <obsolete>
+    Deprecated as of 11/2018.
+  </obsolete>
   <owner>tengs@chromium.org</owner>
   <owner>xiaowenx@chromium.org</owner>
   <summary>
@@ -24939,6 +24942,9 @@ uploading your change for review.
 </histogram>
 
 <histogram name="EasyUnlock.AuthProximity.TransmitPowerDelta" units="dBm">
+  <obsolete>
+    Deprecated as of 11/2018.
+  </obsolete>
   <owner>tengs@chromium.org</owner>
   <owner>xiaowenx@chromium.org</owner>
   <summary>