Improve spec compliance of discarding BCs

[gterzian]

Came-up at #23637 (comment)

---

• ./mach build -d does not report any errors
• ./mach test-tidy does not report any errors
• These changes fix #___ (GitHub issue number if applicable)

• There are tests for these changes OR
• These changes do not require tests because ___

---

This change is 

[highfive]

Heads up! This PR modifies the following files:

• @asajeffrey: components/script/dom/htmliframeelement.rs, components/script/dom/window.rs
• @KiChjang: components/script/dom/htmliframeelement.rs, components/script/dom/window.rs

[highfive]

Warning

• These commits modify script code, but no tests are modified. Please consider adding a test!

[gterzian]

@jdm @asajeffrey r?

The problem is still running tasks after either a frame has been removed from the tree, or an auxiliary closed, in both cases the BC is discarded "sync"(as per the spec), however tasks are only ignored later when the script-thread handles the "exit pipeline" message, which means that in the meantime the global can still be handling tasks. This became apparent in #23637 (comment)

[gterzian]

For good measure I'm also preventing handling any user input via compositor events, since those result in firing events and potentially running JS code, if the BC is being discarded.

(I mentioned something about this not applying to iframe previously, that was wrong, and it is now also applied to them).

[gterzian]

@bors-servo try=wpt

[bors-servo]

⌛ Trying commit c8b7cf0 with merge ab60ff1...

[bors-servo]

💔 Test failed - linux-rel-css

[gterzian]

@bors-servo try=wpt

[bors-servo]

⌛ Trying commit 557d5aa with merge 441285b...

[gterzian]

well, look at that...

{
    "status": "PASS", 
    "group": "default", 
    "message": null, 
    "stack": null, 
    "subtest": "worker-src 'self' directive should disallow cross origin static import.", 
    "test": "/workers/modules/dedicated-worker-import-csp.html", 
    "line": 284199, 
    "action": "test_result", 
    "expected": "FAIL"
}
{
    "status": "PASS", 
    "group": "default", 
    "message": null, 
    "stack": null, 
    "subtest": "script-src 'self' directive should disallow cross origin static import.", 
    "test": "/workers/modules/dedicated-worker-import-csp.html", 
    "line": 284201, 
    "action": "test_result", 
    "expected": "FAIL"
}
{
    "status": "PASS", 
    "group": "default", 
    "message": null, 
    "stack": null, 
    "subtest": "worker-src 'self' directive should override script-src * directive and disallow cross origin static import.", 
    "test": "/workers/modules/dedicated-worker-import-csp.html", 
    "line": 284204, 
    "action": "test_result", 
    "expected": "FAIL"
}
{
    "status": "PASS", 
    "group": "default", 
    "message": null, 
    "stack": null, 
    "subtest": "script-src 'self' directive should disallow cross origin dynamic import.", 
    "test": "/workers/modules/dedicated-worker-import-csp.html", 
    "line": 284205, 
    "action": "test_result", 
    "expected": "FAIL"
}
{
    "status": "OK", 
    "group": "default", 
    "message": null, 
    "stack": null, 
    "subtest": null, 
    "test": "/workers/modules/dedicated-worker-import-csp.html", 
    "line": 284211, 
    "action": "test_result", 
    "expected": "CRASH"
}
{
    "status": "FAIL", 
    "group": "default", 
    "message": "promise_test: Unhandled rejection with value: \"FAIL - first document not exposed. navigated_back is undefined\"", 
    "stack": null, 
    "subtest": "Test that iframe navigations are not observable by the parent, even after history navigations by the parent", 
    "test": "/resource-timing/nested-context-navigations-iframe.html", 
    "line": 303458, 
    "action": "test_result", 
    "expected": "TIMEOUT"
}
{
    "status": "FAIL", 
    "group": "default", 
    "message": "promise_test: Unhandled rejection with value: \"FAIL - first document not exposed. navigated_back is true\"", 
    "stack": null, 
    "subtest": "Test that crossorigin iframe navigations are not observable by the parent, even after history navigations by the parent", 
    "test": "/resource-timing/nested-context-navigations-iframe.html", 
    "line": 303459, 
    "action": "test_result", 
    "expected": "NOTRUN"
}
{
    "status": "FAIL", 
    "group": "default", 
    "message": "promise_test: Unhandled rejection with value: \"FAIL - initial document should be observable\"", 
    "stack": null, 
    "subtest": "Test that iframe navigations are not observable by the parent", 
    "test": "/resource-timing/nested-context-navigations-iframe.html", 
    "line": 303460, 
    "action": "test_result", 
    "expected": "NOTRUN"
}
{
    "status": "FAIL", 
    "group": "default", 
    "message": "promise_test: Unhandled rejection with value: \"FAIL - initial document should be observable\"", 
    "stack": null, 
    "subtest": "Test that crossorigin iframe navigations are not observable by the parent", 
    "test": "/resource-timing/nested-context-navigations-iframe.html", 
    "line": 303461, 
    "action": "test_result", 
    "expected": "NOTRUN"
}
{
    "status": "TIMEOUT", 
    "group": "default", 
    "message": "Test timed out", 
    "stack": null, 
    "subtest": "Test that iframe refreshes are not observable by the parent", 
    "test": "/resource-timing/nested-context-navigations-iframe.html", 
    "line": 303462, 
    "action": "test_result", 
    "expected": "NOTRUN"
}
{
    "status": "TIMEOUT", 
    "group": "default", 
    "message": null, 
    "stack": null, 
    "subtest": null, 
    "test": "/resource-timing/nested-context-navigations-iframe.html", 
    "line": 303464, 
    "action": "test_result", 
    "expected": "CRASH"
}

And also

{
    "status": "CRASH", 
    "group": "default", 
    "message": null, 
    "stack": null, 
    "subtest": null, 
    "test": "/html/browsers/the-window-object/close-method.window.html", 
    "line": 172617, 
    "action": "test_result", 
    "expected": "OK"
}

[gterzian]

@bors-servo try=wpt

[bors-servo]

⌛ Trying commit 5b0980c with merge 86f0b2b...

[bors-servo]

💔 Test failed - linux-rel-wpt

[gterzian]

@bors-servo try=wpt (compilation error, fixed, this time with a local check first)

[bors-servo]

⌛ Trying commit 6b499ce with merge 97ee008...

[bors-servo]

💔 Test failed - linux-rel-wpt

[gterzian]

{
    "status": "FAIL", 
    "group": "default", 
    "message": "/css/css-values/vh-support-transform-translate.html b66c48d9abd17b3672f590a293821101a1847cb9\n/css/css-values/reference/all-green.html ca9048d25067fe2666ee98ffdaee4d41e63aa283", 
    "stack": null, 
    "subtest": null, 
    "test": "/css/css-values/vh-support-transform-translate.html", 
    "line": 38036, 
    "action": "test_result", 
    "expected": "PASS"
}

I think this one might be intermittent

[gterzian]

@asajeffrey ready for another round, see the new commits, to be squashed.

[CYBAI]

I think this one might be intermittent

Yes, it's #23290.

[bors-servo]

☔ The latest upstream changes (presumably #24133) made this pull request unmergeable. Please resolve the merge conflicts.

[gterzian]

@asajeffrey This one is ready for another review.

[asajeffrey]

Yay, this looks like it's quite the improvement! @bors-servo r+

[bors-servo]

📌 Commit 45ec250 has been approved by asajeffrey

[bors-servo]

⌛ Testing commit 45ec250 with merge 75c201f...

[bors-servo]

☀️ Test successful - linux-rel-css, linux-rel-wpt, status-taskcluster
Approved by: asajeffrey
Pushing 75c201f to master...