Origin isolation: implement window.originIsolationRestricted

[chromium-wpt-export-bot]

See WICG/origin-agent-cluster#24 and
WICG/origin-agent-cluster#30 for background,
and whatwg/html#5545 for the specification.

Failing test expectations include:

• We implement (3) from
  Expose isolation state to the page? WICG/origin-agent-cluster#24
  instead of (2) for now, so we fail getter-sandboxed-iframe. Tracking
  at https://crbug.com/1095653.
• The initial about:blank, as well as removed iframes, are not properly
  returning true, so about-blank and removing-iframes are failing. Also
  tracking at https://crbug.com/1095653.
• data: URLs are not [SecureContext] in Chromium
  (https://crbug.com/1095656) so getter-data-url fails.

Note that per ongoing discussion in
WICG/origin-agent-cluster#31 the naming of this
API, as well as its edge-case behavior (e.g. for sandboxed iframes) will
likely change.

Bug: 1042415
Change-Id: I20c2d3e3fec7a5c0f1d12c386999c32fe27b6a34
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2243994
Reviewed-by: Charlie Reis <creis@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: James MacLean <wjmaclean@chromium.org>
Commit-Queue: Domenic Denicola <domenic@chromium.org>
Cr-Commit-Position: refs/heads/master@{#782672}

[wpt-pr-bot]

The review process for this patch is being conducted in the Chromium project.

[LukeZielinski]

One of the test is flaky in Chrome dev (more details below). It seems to crash periodically. Logs show one potentially useful line of output from Chrome:
2:45.23 pid:9968 [1593121997.834][SEVERE]: Unable to receive message from renderer

Unstable results

Test	Subtest	Results	Messages
/origin-isolation/removing-iframes.sub.https.html		ERROR: 5/10, OK: 5/10
/origin-isolation/removing-iframes.sub.https.html	Before: messageerror event must occur	PASS: 5/10, MISSING: 5/10
/origin-isolation/removing-iframes.sub.https.html	Before: setting document.domain must not give sync access	PASS: 5/10, MISSING: 5/10
/origin-isolation/removing-iframes.sub.https.html	parent: originIsolationRestricted must equal true	FAIL: 5/10, MISSING: 5/10	assert_equals: expected (boolean) true but got (undefined) undefined
/origin-isolation/removing-iframes.sub.https.html	child1: originIsolationRestricted must equal false	FAIL: 5/10, MISSING: 5/10	assert_equals: expected (boolean) false but got (undefined) undefined
/origin-isolation/removing-iframes.sub.https.html	Remove the iframe and insert new ones	PASS: 5/10, MISSING: 5/10
/origin-isolation/removing-iframes.sub.https.html	Parent to child2: messageerror event must occur	PASS: 5/10, MISSING: 5/10
/origin-isolation/removing-iframes.sub.https.html	Parent to child2: setting document.domain must not give sync access	PASS: 5/10, MISSING: 5/10
/origin-isolation/removing-iframes.sub.https.html	Parent to child3: messageerror event must occur	PASS: 5/10, MISSING: 5/10
/origin-isolation/removing-iframes.sub.https.html	Parent to child3: setting document.domain must not give sync access	PASS: 5/10, MISSING: 5/10
/origin-isolation/removing-iframes.sub.https.html	child2 to child3: message event must occur	FAIL: 5/10, MISSING: 5/10	assert_equals: expected "WebAssembly.Module message received" but got "messageerror"
/origin-isolation/removing-iframes.sub.https.html	child2 to child3: setting document.domain must give sync access	FAIL: 5/10, MISSING: 5/10	assert_equals: expected "accessed document successfully" but got "SecurityError"
/origin-isolation/removing-iframes.sub.https.html	child3 to child2: message event must occur	FAIL: 5/10, MISSING: 5/10	assert_equals: expected "WebAssembly.Module message received" but got "messageerror"
/origin-isolation/removing-iframes.sub.https.html	child3 to child2: setting document.domain must give sync access	FAIL: 5/10, MISSING: 5/10	assert_equals: expected "accessed document successfully" but got "SecurityError"
/origin-isolation/removing-iframes.sub.https.html	child2: originIsolationRestricted must equal false	FAIL: 5/10, MISSING: 5/10	assert_equals: expected (boolean) false but got (undefined) undefined
/origin-isolation/removing-iframes.sub.https.html	`child

[LukeZielinski]

Filed crbug.com/1099718 to track the flake. @Hexcles could you please admin merge?

[stephenmcgruer]

2:45.23 pid:9968 [1593121997.834][SEVERE]: Unable to receive message from renderer

I suspect that is just recording exactly that the renderer has crashed. We continue to be unable to provide folks with useful logs to debug these problems :(