WordPress/src/main/res/layout/media_browser_activity.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <include
        layout="@layout/toolbar"
        android:id="@+id/toolbar" />

    <LinearLayout
        android:id="@+id/media_browser_container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">

        <fragment
            android:id="@+id/mediaGridFragment"
            android:name="org.wordpress.android.ui.media.MediaGridFragment"
            android:layout_width="match_parent"
            android:layout_height="match_parent" />

        <fragment
            android:id="@+id/mediaAddFragment"
            android:name="org.wordpress.android.ui.media.MediaAddFragment"
            android:layout_width="0dp"
            android:layout_height="0dp" />
    </LinearLayout>

</LinearLayout>