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

components/proximity_auth/messenger_impl.h

Index: components/proximity_auth/messenger_impl.h
diff --git a/components/proximity_auth/messenger_impl.h b/components/proximity_auth/messenger_impl.h
index 47310a034410340e6035602aca165deb76c704a1..e7c7fd5d10a7a900878a78b5564b36f0d92deea4 100644
--- a/components/proximity_auth/messenger_impl.h
+++ b/components/proximity_auth/messenger_impl.h
@@ -44,6 +44,7 @@ class MessengerImpl : public Messenger, public cryptauth::ConnectionObserver {
   void RequestDecryption(const std::string& challenge) override;
   void RequestUnlock() override;
   cryptauth::SecureContext* GetSecureContext() const override;
+  cryptauth::Connection* GetConnection() const override;
 
   // Exposed for testing.
   cryptauth::Connection* connection() { return connection_.get(); }