conversations-classic/src/main/res/layout/message_date_bubble.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    android:paddingLeft="8dp"
    android:paddingTop="5dp"
    android:paddingRight="8dp"
    android:paddingBottom="5dp">

    <LinearLayout
        android:id="@+id/message_box"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:background="@drawable/date_bubble_white">

        <TextView
            android:id="@+id/message_body"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textAppearance="@style/TextAppearance.Conversations.Body1.Secondary"
            tools:text="Yesterday" />
    </LinearLayout>

</RelativeLayout>