website_blog/wizard/document_page_show_diff_view.xml

<?xml version="1.0" encoding="utf-8"?>
<openerp>
    <data>

        <!-- Create Index Form view  -->
        <record id="view_wiki_show_diff" model="ir.ui.view">
            <field name="name">Show Difference</field>
            <field name="model">blog.post.history.show_diff</field>
            <field name="arch" type="xml">
                <form string="Difference">
                    <field name="diff" widget="html" options='{"safe": True}'/>
                    <footer>
                        <button string="Cancel" class="oe_link" special="cancel" />
                    </footer>
                </form>
            </field>
        </record>
        <!-- Create Index Action  -->
        <record id="action_view_wiki_show_diff" model="ir.actions.act_window">
            <field name="name">Difference</field>
            <field name="type">ir.actions.act_window</field>
            <field name="res_model">blog.post.history.show_diff</field>
            <field name="view_type">form</field>
            <field name="view_mode">form</field>
            <field name="target">new</field>
        </record>
        <!-- Create Index Action Window  -->
        <act_window 
            id="action_view_wiki_show_diff_values"
            key2="client_action_multi"
            name="Difference"
            res_model="blog.post.history.show_diff"
            src_model="blog.post.history"
            view_mode="form"
            target="new"
            view_type="form"/>

    </data>
</openerp>