Sync WPT with upstream (14-02-2020)

[servo-wpt-sync]

Automated downstream sync of changes from upstream as of 14-02-2020.
[no-wpt-sync]
r? @servo-wpt-sync

[servo-wpt-sync]

@bors-servo r+

[bors-servo]

📌 Commit 12de475 has been approved by servo-wpt-sync

[bors-servo]

⌛ Testing commit 12de475 with merge 9473c45...

[highfive]

Heads up! This PR modifies the following files:

• @jgraham: tests/wpt/webgl/meta/MANIFEST.json

[bors-servo]

💔 Test failed - status-taskcluster

[jdm]

Error running mach:
    ['test-tidy', '--no-progress', '--all']
The error occurred in code that was called by the mach command. This is either
a bug in the called code itself or in the way that mach is calling it.
You can invoke |./mach busted| to check if this issue is already on file. If it
isn't, please use |./mach busted file| to report it. If |./mach busted| is
misbehaving, you can also inspect the dependencies of bug 1543241.
If filing a bug, please include the full output of mach, including this error
message.
The details of the failure are as follows:
KeyError: 'paths'
  File "/repo/python/servo/testing_commands.py", line 341, in test_tidy
    manifest_dirty = run_update(self.context.topdir, check_clean=True)
  File "/repo/python/servo/testing_commands.py", line 98, in run_update
    return manifestupdate.update(logger, wpt_dir, check_clean, rebuild)
  File "/repo/tests/wpt/manifestupdate.py", line 56, in update
    return _check_clean(logger, test_paths)
  File "/repo/tests/wpt/manifestupdate.py", line 107, in _check_clean
    if not diff_manifests(logger, manifest_path, old_manifest, new_manifest):
  File "/repo/tests/wpt/manifestupdate.py", line 170, in diff_manifests
    for (key, value) in iteritems(new_manifest.to_json()["paths"])}

[jdm]

 ▶ Unexpected subtest result in /_mozilla/mozilla/window-postmessage-sameorigin.html:
  │ FAIL [expected PASS] any origin, non-cloneable message (handler)
  │   → assert_throws is not defined

All uses of assert_throws in mozilla tests need to be replaced.

  ▶ PASS [expected FAIL] /css/css-text/white-space/trailing-other-space-separators-break-spaces-012.html
  ▶ Unexpected subtest result in /css/CSS2/floats/hit-test-floats-004.html:
  └ PASS [expected FAIL] Miss float below something else

  ▶ TIMEOUT [expected OK] /html/webappapis/scripting/processing-model-2/integration-with-the-javascript-job-queue/promise-job-entry.html
  │ 
  │ 
  │ 
  │ 
  │ [2020-02-14T11:52:40Z ERROR servo::browser] Multiple top level browsing contexts not supported yet.
  │ [2020-02-14T11:52:40Z ERROR servo::browser] Multiple top level browsing contexts not supported yet.
  │ [2020-02-14T11:52:40Z ERROR servo::browser] Multiple top level browsing contexts not supported yet.
  │ [2020-02-14T11:52:40Z ERROR servo::browser] Multiple top level browsing contexts not supported yet.
  │ [2020-02-14T11:52:40Z ERROR servo::browser] Multiple top level browsing contexts not supported yet.
  └ [2020-02-14T11:52:40Z ERROR servo::browser] Multiple top level browsing contexts not supported yet.
  ▶ Unexpected subtest result in /html/webappapis/scripting/processing-model-2/integration-with-the-javascript-job-queue/promise-job-entry.html:
  │ TIMEOUT [expected FAIL] Fulfillment handler on pending-then-fulfilled promise
  └   → Test timed out
  ▶ Unexpected subtest result in /html/webappapis/scripting/processing-model-2/integration-with-the-javascript-job-queue/promise-job-entry.html:
  │ TIMEOUT [expected FAIL] Rejection handler on pending-then-rejected promise
  └   → Test timed out

  ▶ PASS [expected FAIL] /css/css-text/line-breaking/line-breaking-atomic-003.html

[bors-servo]

☔ The latest upstream changes (presumably #25674) made this pull request unmergeable. Please resolve the merge conflicts.

[jdm]

https://github.com/web-platform-tests/rfcs/pull/29/files

[CYBAI]

Close in favor of #25779