Runtime type check webdriver.client

[gsnedders]

Having locally seen a request to POST /session/None/timeouts, clearly we aren't doing enough validation. This may well be indicative of bugs in the library, but we shouldn't be accidentally stringifying non-str types and sending them over the wire.

While we're at it, remove webdriver.client.Cookies because this has been dead since it was first added in 7033fdd and its __setitem__ is pretty broken (referring to a bogus WebDriver command, seemingly confusing name and value, and referring to some mysterious value.value), and adding a type check there just makes it more apparent how bogus it is.

[foolip]

Changes look good, but are any of these errors hit in a full run?

[gsnedders]

Changes look good, but are any of these errors hit in a full run?

I haven't actually tried a full run; the times I've seen this are mostly cases where the browser has crashed in the middle of a wdspec test, where we're meant to create a new session for each command (which is also kinda suspect behaviour!) but then the relevant API doesn't. That should also be fixed, but it's a separate issue to this.

[gsnedders]

@web-platform-tests/admins Can someone please force-merge this? See #51981, #51984, #51985. Having retriggered the runs three times now, I don't think we're going to get a clean run.

[darktears]

While trying to rollout a newer WPT into Chromium this PR showed regression into two tests:

• webdriver/tests/classic/close_window/close.py
• webdriver/tests/classic/delete_session/delete.py

The run is located here.
https://ci.chromium.org/ui/p/chromium/builders/try/linux-blink-rel/119506/overview

The failures are:

For close_window/close:

This is a wdspec test.
[ERROR] test_close_last_browsing_context
  teardown error: TypeError: Session.session_id must be a str to send a session command
Harness: the test ran to completion.

For delete_session/delete:

This is a wdspec test.
[ERROR] test_null_response_value
  teardown error: TypeError: Session.session_id must be a str to send a session command
[ERROR] test_accepted_beforeunload_prompt
  teardown error: TypeError: Session.session_id must be a str to send a session command
Harness: the test ran to completion.

I'm not familiar at all with the code and what it tries to do. Is it something wrong with the tests? The patch?