Android API 21 Toolbar Padding

Question

How do I get rid of the extra padding in the new Toolbar with Android SDK API version 21 (the support library)?

I am talking about the red arrows on this picture:

Here is the code I am using:

<android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_height="wrap_content"
        android:layout_width="match_parent"
        android:background="?attr/colorPrimary"
        android:padding="0dp"
        android:layout_margin="0dp">

        <RelativeLayout
            android:id="@+id/action_bar_layout"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_margin="0dp"
            android:padding="0dp"
            android:background="#000000">

            <Spinner
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"/>

        </RelativeLayout>
</Toolbar>

As you can see I've set all the relevant padding to 0, but there is still padding around the Spinner. What have I done wrong or what do I need to do to get rid of the extra padding?

Edit Some have questioned why I am trying to do this.

As per the Material Design specs, the spinner should be 72dp from the left side

I need to neutralize the padding Google have put there in order to properly place my spinner:

Edit 2

As per Chris Bane's answer below I set the contentInsetStart to 0. For the support library you will need to use the app namespace:

<android.support.v4.widget.DrawerLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

     <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_height="wrap_content"
        android:layout_width="match_parent"
        android:minHeight="@dimen/action_bar_height"
        android:background="?attr/colorPrimary"
        android:contentInsetStart="0dp"
        android:contentInsetLeft="0dp"
        app:contentInsetLeft="0dp"
        app:contentInsetStart="0dp"
        app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
        app:popupTheme="@style/ThemeOverlay.AppCompat.Light">

</android.support.v4.widget.DrawerLayout>

I hope this helps someone, it had me confused for several days.

Answer 1

The left inset is caused by Toolbar's contentInsetStart which by default is 16dp.

Change this to 72dp to align to the keyline.

Update for support library v24.0.0:

To match the Material Design spec there's an additional attribute contentInsetStartWithNavigation which by default is 16dp. Change this if you also have a navigation icon.