tachiyomi/app/src/main/res/layout/webview_activity.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/web_view_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <LinearLayout
        android:orientation="vertical"
        android:id="@+id/web_linear_layout"
        android:layout_width="match_parent"
        android:fitsSystemWindows="true"
        android:layout_height="match_parent">

        <androidx.appcompat.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="?attr/colorPrimary"
            android:theme="?attr/actionBarTheme"
            app:navigationIcon="@drawable/ic_close_white_24dp"/>

        <WebView
            android:id="@+id/webview"
            android:layout_width="match_parent"
            android:layout_height="match_parent">

        </WebView>
    </LinearLayout>
</FrameLayout>