Unknown toolbar margin while using Design library android

Question

How can I remove the start and end margin from the toolbar?

Below is my xml:

<?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.test.activities.topup.CreditCardDetailsVerification">

<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="?attr/actionBarSize"
        app:popupTheme="@style/AppTheme.PopupOverlay"/>

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

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

style.xml

<style name="AppTheme.AppBarOverlay" parent="ThemeOverlay.AppCompat.Dark.ActionBar">
    <item name="android:background">@android:color/transparent</item>
</style>

style.xml (v21)

<style name="AppTheme.AppBarOverlay" parent="ThemeOverlay.AppCompat.Dark.ActionBar">
    <item name="android:background">@android:color/transparent</item>
    <item name="android:backgroundTint">@android:color/transparent</item>
</style>

Answer 1

I figured it out. It was <item name="android:backgroundTint">@android:color/transparent</item> which causing this issue. I removed it and margin from start and end of toolbar is also removed.