Como incluir um search no xml de uma toolbar no android?

gostaria de saber como adicionar um campo de search no xml de numa toolbar?

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:context="com.grsoft.gfood.MainActivity">

    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/AppTheme.AppBarOverlay">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="141dp"
            android:background="@color/colorAccent"
            app:popupTheme="@style/AppTheme.PopupOverlay"
            android:orientation="vertical"
            android:weightSum="1">

        </android.support.v7.widget.Toolbar>



        <android.support.design.widget.TabLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="@color/colorPrimaryDark"
            app:tabTextColor="@color/colorPrimary"
            app:tabSelectedTextColor="@color/colorPrimary"
            android:id="@+id/tab_layout_main"
            app:tabMode="fixed"
            app:tabGravity="fill"
            app:tabIndicatorColor="@android:color/darker_gray">

            <android.support.design.widget.TabItem
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="@string/proximo" />

            <android.support.design.widget.TabItem
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="@string/japonesa"/>

            <android.support.design.widget.TabItem
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="@string/chinesa"/>

            <android.support.design.widget.TabItem
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="@string/lanche"/>

        </android.support.design.widget.TabLayout>

    </android.support.design.widget.AppBarLayout>


    <include layout="@layout/content_main" />


</android.support.design.widget.CoordinatorLayout>