web/web_tree_dynamic_colored_field/demo/res_users.xml

<?xml version="1.0" encoding="UTF-8"?>
<openerp>
    <data>
        <record id="view_users_tree" model="ir.ui.view">
            <field name="model">res.users</field>
            <field name="inherit_id" ref="base.view_users_tree" />
            <field name="arch" type="xml">
                <xpath expr="." position="attributes">
                    <attribute name="color_field">lang</attribute>
                </xpath>
                <field name="login_date" position="attributes">
                    <attribute name="bg_color">red: login_date == False</attribute>
                    <attribute name="fg_color">white: login_date == False</attribute>
                </field>
                <field name="name" position="attributes">
                    <attribute name="bg_color">red: login == 'admin'</attribute>
                    <attribute name="fg_color">white: login == 'admin'</attribute>
                </field>
            </field>
        </record>
    </data>
</openerp>