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

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

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

    <FrameLayout
        android:id="@+id/layout_fragment_container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context="org.wordpress.android.ui.comments.CommentsActivity"/>
</LinearLayout>