chromium/android_webview/tools/system_webview_shell/apk/res/layout/activity_web_platform_tests_child.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:id="@+id/childLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
  <LinearLayout
      android:orientation="horizontal"
      android:layout_width="match_parent"
      android:padding="0dp"
      android:layout_height="wrap_content"
      android:layout_marginStart="0dp"
      android:layout_marginTop="0dp"
      android:id="@+id/childTopControls">
    <Button
        android:text="@string/close_button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="5dp"
        android:padding="0dp"
        android:paddingTop="0dp"
        android:id="@+id/childCloseButton"/>
    <TextView
        android:id="@+id/childTitleText"
        android:layout_marginTop="5dp"
        android:layout_marginBottom="5dp"
        android:layout_marginStart="0dp"
        android:layout_marginEnd="65dp"
        android:layout_width="match_parent"
        android:layout_height="30dp"
        android:gravity="center"
        android:scrollHorizontally="true"
        android:ellipsize="end"
        android:maxLines="1"
        android:textStyle="bold"
        android:textColor="@android:color/white"
        />
  </LinearLayout>
  <WebView
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:id="@+id/childWebView"
      />
</LinearLayout>