Custom background of ActionBar Compat

Custom background of ActionBar Compat

I am using Action Bar Compat so that my action bar with navigation drawer
was backward compatible down to API level 9 and I want to change the
background of the action bar.
I copied the code from Android Developers:
<?xml version="1.0" encoding="utf-8"?>
<resources>
<!-- the theme applied to the application or activity -->
<style name="CustomActionBarTheme"
parent="@style/Theme.AppCompat.Light.DarkActionBar">
<item name="android:actionBarStyle">@style/MyActionBar</item>
<!-- Support library compatibility -->
<item name="actionBarStyle">@style/MyActionBar</item>
</style>
<!-- ActionBar styles -->
<style name="MyActionBar"
parent="@style/Widget.AppCompat.Light.ActionBar.Solid.Inverse">
<item name="android:background">@drawable/actionbar_background</item>
<!-- Support library compatibility -->
<item name="background">@drawable/actionbar_background</item>
</style>
</resources>
And here comes the problem.
When I put an image drawable as a background, it works. However I want to
define the background as a gradient shape, so my actionbar_background
looks like:
<?xml version="1.0" encoding="utf-8"?>
<shape
xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="line">
<gradient
android:startColor="@color/ac_bg_start"
android:endColor="@color/ac_bg_end"
android:type="linear"/>
<size
android:width="1dp"
android:height="48dp"/>
</shape>
I want it to be repeated in horizontal way but even this result in error.
I was able to catch DeadObjectException before restarting.
How should the background drawable look like?