[Smart Lock] Add error message strings for the "Tx Power too high" case.

chrome/browser/chromeos/login/easy_unlock/easy_unlock_metrics.h

Index: chrome/browser/chromeos/login/easy_unlock/easy_unlock_metrics.h
diff --git a/chrome/browser/chromeos/login/easy_unlock/easy_unlock_metrics.h b/chrome/browser/chromeos/login/easy_unlock/easy_unlock_metrics.h
index 11489e8de9d12a0b4651f7560085d1b1c261ac46..b1779169f92aac1703b4b59c5a542a1fed5ee582 100644
--- a/chrome/browser/chromeos/login/easy_unlock/easy_unlock_metrics.h
+++ b/chrome/browser/chromeos/login/easy_unlock/easy_unlock_metrics.h
@@ -58,6 +58,9 @@ enum EasyUnlockLoginEvent {
   // Most likely because EasyUnlock is disabled, e.g. Bluetooth adapter not
   // ready.
   PASSWORD_SIGN_IN_NO_SCREENLOCK_STATE_HANDLER = 18,
+  // Password is used for sign-in because the phone is (a) locked, and (b) not
+  // right next to the Chromebook.
+  PASSWORD_SIGN_IN_PHONE_LOCKED_AND_TX_POWER_TOO_HIGH = 19,
 
   EASY_SIGN_IN_LOGIN_EVENT_COUNT  // Must be the last.
 };