It's not clear when and how this happened but apparently "headful"
chrome has a built-in background_page for hangouts which appears
before the `about:blank` page in the list of targets, and possibly
appears before the `about:blank` page has opened at all.
odoo/odoo#111422 was tested with chromium which apparently doesn't
have this feature either (or does it?), which probably contributes to
having no idea when it appears.
This feature also doesn't respond to `--disable-extensions`, despite
its url marking it as one:
chrome-extension://nkeimhogjdpnpccoofpliimaahmaaome/background.html
The result was that the tour runner would hook onto the hangouts
target and try to load pages, which it would reject with
`net::ERR_ABORTED`, hence the tours just getting stuck.
Fix by improving the heuristic to find a content page: look for a
target of type `page`, and with the url `about:blank`, rather than
just take whichever tab target is listed first. Requires modifying
`stop` as it can now be called after we've started the browser, but
before we've created the websocket connection.
Also move `--no-first-run` from the headless to the default switches
to avoid Chrome's migration & default browser popup, apparently it
doesn't cause Chromium grief anymore (???). If this turns out to be a
concern, add a condition on the `executable` or something.
closesodoo/odoo#122117
Signed-off-by: Xavier Morel (xmo) <xmo@odoo.com>