ring-android/app/src/main/res/menu/ac_call.xml

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android" >

    <item
        android:id="@+id/menuitem_chat"
        android:showAsAction="always"
        android:icon="@drawable/ic_chat_white_24dp"
        android:title="@string/ab_action_chat"/>

</menu>