[FIX] website: prevent tb when using a background video as cover

Prior to this commit, when using a background video on the cover of the
website_slides homepage (/slides), after saving, a traceback would
occur and the video would not be displayed.

Steps to reproduce:
- Install website_slide
- Go to /slides
- Enter edit mode
- Change the cover of the page by a video
- Save
- Traceback

The reason for that is that the cover snippet used on the homepage of
elearning is the root of an XPath instead of its own oe_structure. (This
was changed in 16.0)
[1] made it so that the style and class attributes are saved but did not
save any data attributes needed for the background-video widget to work.

This commit adds those data attributes.

[1]: https://github.com/odoo/odoo/commit/5b252215dc375526af87c31a32256dd1a9582f02

opw-3063043

closes odoo/odoo#107577

X-original-commit: 86dc4d4349d033c95c0e04e8c173f63e5e2044ed
Signed-off-by: Romain Derie (rde) <rde@odoo.com>

addons/web_editor/models/ir_ui_view.py

@@ -117,6 +117,10 @@ class IrUiView(models.Model):
             return False
         return all(self._are_archs_equal(arch1, arch2) for arch1, arch2 in zip(arch1, arch2))
 
+    @api.model
+    def _get_allowed_root_attrs(self):
+        return ['style', 'class']
+
     def replace_arch_section(self, section_xpath, replacement, replace_tail=False):
         # the root of the arch section shouldn't actually be replaced as it's
         # not really editable itself, only the content truly is editable.
@@ -132,7 +136,7 @@ class IrUiView(models.Model):
         root.text = replacement.text
 
         # We need to replace some attrib for styles changes on the root element
-        for attribute in ('style', 'class'):
+        for attribute in self._get_allowed_root_attrs():
             if attribute in replacement.attrib:
                 root.attrib[attribute] = replacement.attrib[attribute]
 

addons/website/models/ir_ui_view.py

@@ -484,6 +484,14 @@ class View(models.Model):
                 self = website_specific_view
         super(View, self).save(value, xpath=xpath)
 
+    @api.model
+    def _get_allowed_root_attrs(self):
+        # Related to these options:
+        # background-video, background-shapes, parallax
+        return super()._get_allowed_root_attrs() + [
+            'data-bg-video-src', 'data-shape', 'data-scroll-background-ratio',
+        ]
+
     # --------------------------------------------------------------------------
     # Snippet saving
     # --------------------------------------------------------------------------