[components] Autofill: Show fallback if login is empty.

X-Channel-Revision: [main] mozilla-mobile/android-components@cf522a7
X-Channel-Revision: [main] mozilla-mobile/fenix@20b25d7
X-Channel-Revision: [main] mozilla-mobile/focus-android@29486b8
X-Channel-Converted-Revision: [ac-prep] mozilla-mobile/firefox-android@8da64a1

_meta/mozilla-mobile-firefox-android.json

@@ -1,6 +1,6 @@
 {
   "name": "mozilla-mobile/firefox-android",
   "revs": {
-    "ac-prep": "100247ffdcff216151614933690c7dc9532187c2"
+    "ac-prep": "8da64a1a02d9d451f7a9e90242d76b7750a6e5f9"
   }
 }

mozilla-mobile/android-components/components/feature/autofill/src/main/res/values/strings.xml

@@ -4,4 +4,13 @@
      a username or password can be autofilled for the highlighted text field. %1$s will be replaced
      with the name of the browser application (e.g. Firefox) -->
     <string name="mozac_feature_autofill_popup_unlock_application">Unlock %1$s</string>
+
+    <!-- Autofill: Text shown in popup in third-party app if we found a matching account, but no
+    username is saved (e.g. we only have a password). This text will be shown in place where otherwise
+    the username would be displayed. -->
+    <string name="mozac_feature_autofill_popup_no_username">(No username)</string>
+
+    <!-- Autofill: Text shown in popup in third-party app to autofill the password for an account.
+    %1$s will be replaced with the login/username of the account. -->
+    <string name="mozac_feature_autofill_popup_password">Password for %1$s</string>
 </resources>