How to create standard Borderless buttons (like in the design guideline mentioned)?

To clear some confusion:

This is done in 2 steps: Setting the button background attribute to android:attr/selectableItemBackground creates you a button with feedback but no background.

android:background="?android:attr/selectableItemBackground"

The line to divide the borderless button from the rest of you layout is done by a view with the background android:attr/dividerVertical

android:background="?android:attr/dividerVertical"

For a better understanding here is a layout for a OK / Cancel borderless button combination at the bottom of your screen (like in the right picture above).

<RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="48dp"
        android:layout_alignParentBottom="true">
        <View
            android:layout_width="match_parent"
            android:layout_height="1dip"
            android:layout_marginLeft="4dip"
            android:layout_marginRight="4dip"
            android:background="?android:attr/dividerVertical"
            android:layout_alignParentTop="true"/>
        <View
            android:id="@+id/ViewColorPickerHelper"
            android:layout_width="1dip"
            android:layout_height="wrap_content"
            android:layout_alignParentTop="true"
            android:layout_alignParentBottom="true"
            android:layout_marginBottom="4dip"
            android:layout_marginTop="4dip"
            android:background="?android:attr/dividerVertical" 
            android:layout_centerHorizontal="true"/>
        <Button
            android:id="@+id/BtnColorPickerCancel"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentLeft="true"
            android:layout_alignParentTop="true"
            android:layout_toLeftOf="@id/ViewColorPickerHelper"
            android:background="?android:attr/selectableItemBackground"
            android:text="@android:string/cancel" 
            android:layout_alignParentBottom="true"/>
        <Button
            android:id="@+id/BtnColorPickerOk"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:layout_alignParentRight="true"
            android:layout_alignParentTop="true"
            android:background="?android:attr/selectableItemBackground"
            android:text="@android:string/ok" 
            android:layout_alignParentBottom="true" 
            android:layout_toRightOf="@id/ViewColorPickerHelper"/>
    </RelativeLayout>

Simply add the following style attribute in your Button tag:

    style="?android:attr/borderlessButtonStyle"

source: http://developer.android.com/guide/topics/ui/controls/button.html#Borderless

Then you can add dividers as in Karl's answer.

Late answer, but many views. As APIs < 11 ain't dead yet, for those interested here is a trick.

Let your container have the desired color (may be transparent). Then give your buttons a selector with default transparent color, and some color when pressed. That way you'll have a transparent button, but will change color when pressed (like holo's). You can also add some animation (like holo's). The selector should be something like this:

res/drawable/selector_transparent_button.xml
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android" 
          android:exitFadeDuration="@android:integer/config_shortAnimTime">
     <item android:state_pressed="true"
         android:drawable="@color/blue" />

   <item android:drawable="@color/transparent" />
</selector>

And the button should have android:background="@drawable/selector_transparent_button"

PS: let you container have the dividers (android:divider='@android:drawable/... for API < 11)

PS [Newbies]: you should define those colors in values/colors.xml