[FIX] ir_qweb: post process the attributes in widget html value

issue: Blog doe not use the cdn because the widget html value is not
compiled by the qweb and does not use the attribute post processing.

addons/website/tests/template_qweb_test.xml

@@ -26,6 +26,9 @@
         <img src="/website/static/img.png"/>
         <a href="http://test.external.link/link">x</a>
         <a href="/web/content/local_link">x</a>
+        <span t-attf-style="background-image: url('/web/image/2')" t-att-empty="False">xxx</span>
+        <div widget="html" t-field="user.signature"/>
+        <div widget="image" t-field="user.image" t-options="{'widget': 'image'}"/>
     </body>
 </html>
     </template>

addons/website/tests/test_qweb.py

@@ -1,6 +1,8 @@
 # -*- coding: utf-8 -*-
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 
+import re
+
 from odoo import tools
 from odoo.modules.module import get_module_resource
 from odoo.tests.common import TransactionCase
@@ -22,18 +24,24 @@ class TestQweb(TransactionCase):
         })
 
         demo = self.env['res.users'].search([('login', '=', 'demo')])[0]
+        demo.write({"signature": '''<span class="toto">
+                span<span class="fa"></span><img src="/web/image/1"/>
+            </span>'''})
+
         demo_env = self.env(user=demo)
 
-        html = demo_env['ir.qweb'].render('website.test_template', {}, website_id= website.id)
+        html = demo_env['ir.qweb'].render('website.test_template', {"user": demo}, website_id= website.id)
+        html = html.strip().decode('utf8')
+        html = re.sub(r'\?unique=[^"]+', '', html).encode('utf8')
 
         attachments = demo_env['ir.attachment'].search([('url', '=like', '/web/content/%-%/website.test_bundle.%')])
-        self.assertEquals(len(attachments), 2)
-        self.assertEqual(html.strip(), """<!DOCTYPE html>
+        self.assertEqual(len(attachments), 2)
+        self.assertEqual(html, ("""<!DOCTYPE html>
 <html>
     <head>
         <link rel="stylesheet" href="http://test.external.link/style1.css"/>
         <link rel="stylesheet" href="http://test.external.link/style2.css"/>
-        <link href="http://test.cdn%(css)s" rel="stylesheet"/>
+        <link type="text/css" rel="stylesheet" href="http://test.cdn%(css)s"/>
         <meta/>
         <script type="text/javascript" src="http://test.external.link/javascript1.js"></script>
         <script type="text/javascript" src="http://test.external.link/javascript2.js"></script>
@@ -44,5 +52,14 @@ class TestQweb(TransactionCase):
         <img src="http://test.cdn/website/static/img.png"/>
         <a href="http://test.external.link/link">x</a>
         <a href="http://test.cdn/web/content/local_link">x</a>
+        <span style="background-image: url('http://test.cdn/web/image/2')">xxx</span>
+        <div widget="html"><span class="toto">
+                span<span class="fa"></span><img src="http://test.cdn/web/image/1">
+            </span></div>
+        <div widget="image"><img src="http://test.cdn/web/image/res.users/%(user_id)s/image" class="img img-responsive"/></div>
     </body>
-</html>""" % {"js": attachments[0].url, "css": attachments[1].url})
+</html>""" % {
+            "js": attachments[0].url,
+            "css": attachments[1].url,
+            "user_id": demo.id,
+        }).encode('utf8'))

odoo/addons/base/ir/ir_qweb/fields.py

@@ -6,6 +6,8 @@ from io import BytesIO
 from odoo import api, fields, models, _
 from PIL import Image
 import babel
+from lxml import etree
+
 from odoo.tools import html_escape as escape, posix_to_ldml, safe_eval, float_utils, format_date, pycompat
 
 import logging
@@ -252,7 +254,17 @@ class HTMLConverter(models.AbstractModel):
 
     @api.model
     def value_to_html(self, value, options):
-        return pycompat.to_text(value)
+        irQweb = self.env['ir.qweb']
+        # wrap value inside a body and parse it as HTML
+        body = etree.fromstring("<body>%s</body>" % value, etree.HTMLParser(encoding='utf-8'))[0]
+        # use pos processing for all nodes with attributes
+        for element in body.iter():
+            if element.attrib:
+                attrib = OrderedDict(element.attrib)
+                attrib = irQweb._post_processing_att(element.tag, attrib, options)
+                element.attrib.clear()
+                element.attrib.update(attrib)
+        return etree.tostring(body, encoding='unicode', method='html')[6:-7]
 
 
 class ImageConverter(models.AbstractModel):

odoo/addons/base/ir/ir_qweb/ir_qweb.py

@@ -341,6 +341,11 @@ class IrQWeb(models.AbstractModel, QWeb):
     def _get_field(self, record, field_name, expression, tagName, field_options, options, values):
         field = record._fields[field_name]
 
+        # adds template compile options for rendering fields
+        for k, v in options.items():
+            field_options.setdefault(k, v)
+
+        # adds generic field options
         field_options['tagName'] = tagName
         field_options['expression'] = expression
         field_options['type'] = field_options.get('widget', field.type)

odoo/addons/base/ir/ir_qweb/qweb.py

@@ -5,7 +5,7 @@ import os.path
 import re
 import traceback
 
-from collections import OrderedDict, Sized, Mapping, defaultdict
+from collections import OrderedDict, Sized, Mapping
 from functools import reduce
 from itertools import tee, count
 from textwrap import dedent