[EasyUnlock] Update ProximityMonitor to only check for RSSI proximity.

components/proximity_auth/proximity_monitor.h

Index: components/proximity_auth/proximity_monitor.h
diff --git a/components/proximity_auth/proximity_monitor.h b/components/proximity_auth/proximity_monitor.h
index b2978bf170d3ad8a792b766fab62ae155f78aec6..b441ccedc4792bf1ea53cec4f2bcc74e4951794f 100644
--- a/components/proximity_auth/proximity_monitor.h
+++ b/components/proximity_auth/proximity_monitor.h
@@ -13,8 +13,6 @@ namespace proximity_auth {
 // sufficiently close to the local device to permit unlocking.
 class ProximityMonitor {
  public:
-  enum class Strategy { NONE, CHECK_RSSI, CHECK_TRANSMIT_POWER };
-
   virtual ~ProximityMonitor() {}
 
   // Activates the proximity monitor. No-op if the proximity monitor is already
@@ -25,18 +23,10 @@ class ProximityMonitor {
   // already inactive.
   virtual void Stop() = 0;
 
-  // Returns the strategy used to determine whether the remote device is in
-  // proximity.
-  virtual Strategy GetStrategy() const = 0;
-
   // Returns |true| iff the remote device is close enough to the local device,
   // given the user's current settings.
   virtual bool IsUnlockAllowed() const = 0;
 
-  // Returns |true| iff the remote device is close enough to the local device,
-  // according to its RSSI measurement.
-  virtual bool IsInRssiRange() const = 0;
-
   // Records the current proximity measurements to UMA. This should be called
   // when the user successfully authenticates using proximity auth.
   virtual void RecordProximityMetricsOnAuthSuccess() = 0;