gecko/embedding/android/resources/layout/gecko_app.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:id="@+id/main_layout"
              style="@style/Screen">

    <org.mozilla.gecko.BrowserToolbar android:id="@+id/browser_toolbar"
                                      style="@style/BrowserToolbar"/>

    <AbsoluteLayout android:id="@+id/gecko_layout"
                    android:layout_width="fill_parent"
                    android:layout_height="fill_parent"
                    android:layout_weight="1"/>

 </LinearLayout>