[COOP] Access reporting [11/N] Fix wrong accessing context used.

There are 3 function to get a DomWindow from an isolate:
- LocalDOMWindow* EnteredDOMWindow(v8::Isolate*);
- LocalDOMWindow* IncumbentDOMWindow(v8::Isolate*);
- LocalDOMWindow* CurrentDOMWindow(v8::Isolate*);

The difference is explained by:
third_party/blink/renderer/bindings/core/v8/V8BindingDesign.md

For same-origin accesses to a window's method, the wrong V8 context was
used. Instead of being the "calling" context, it was the "called"
context.

Using IncumbentDomWindow instead of CurrentDOMWindow fixed the issue.
See response from:
https://bugs.chromium.org/p/chromium/issues/detail?id=1109153#c2

COOP access reporting:
[ 1/N] https://chromium-review.googlesource.com/c/chromium/src/+/2264294
[ 2/N] https://chromium-review.googlesource.com/c/chromium/src/+/2270185
[ 3/N] https://chromium-review.googlesource.com/c/chromium/src/+/2270472
[ 4/N] https://chromium-review.googlesource.com/c/chromium/src/+/2273120
[ 5/N] https://chromium-review.googlesource.com/c/chromium/src/+/2309433
[ 6/N] https://chromium-review.googlesource.com/c/chromium/src/+/2308715
[ 7/N] https://chromium-review.googlesource.com/c/chromium/src/+/2309697
[ 8/N] https://chromium-review.googlesource.com/c/chromium/src/+/2275889
[ 9/N] https://chromium-review.googlesource.com/c/chromium/src/+/2310530
[10/N] https://chromium-review.googlesource.com/c/chromium/src/+/2315024
[11/N] this patch.

Bug: 1090273
Change-Id: I3da021c33af25831a242f64ff732556aa6775a46
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2323250Reviewed-by: Yuki Shiino <yukishiino@chromium.org>
Reviewed-by: Camille Lamy <clamy@chromium.org>
Auto-Submit: Arthur Sonzogni <arthursonzogni@chromium.org>
Commit-Queue: Arthur Sonzogni <arthursonzogni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#792671}

third_party/blink/renderer/core/frame/dom_window.cc

@@ -450,7 +450,7 @@ void DOMWindow::ReportCoopAccess(v8::Isolate* isolate,
   if (coop_access_monitor_.IsEmpty())  // Fast early return. Very likely true.
     return;
 
-  DOMWindow* accessing_window = CurrentDOMWindow(isolate);
+  LocalDOMWindow* accessing_window = IncumbentDOMWindow(isolate);
   Frame* accessing_frame = accessing_window->GetFrame();
 
   // A frame might be destroyed, but its context can still be able to execute

third_party/blink/web_tests/external/wpt/html/cross-origin-opener-policy/reporting/access-reporting/openee-accessed_opener-coop-ro.https-expected.txt

-This is a testharness.js-based test.
-FAIL Opener (COOP-RO+COEP) accesses openee. Report to opener assert_not_equals: Report not received got disallowed value "timeout"
-Harness: the test ran to completion.
-

third_party/blink/web_tests/external/wpt/html/cross-origin-opener-policy/reporting/access-reporting/opener-accessed_opener-coop-ro.https-expected.txt

-This is a testharness.js-based test.
-FAIL Openee accesses opener (COOP-RO-COEP). Report to opener assert_not_equals: Report not received got disallowed value "timeout"
-Harness: the test ran to completion.
-

third_party/blink/web_tests/external/wpt/html/cross-origin-opener-policy/reporting/access-reporting/property.https-expected.txt

@@ -16,10 +16,10 @@ PASS cross-origin > w => w.postMessage("", "")
 PASS cross-origin > w => w.self
 PASS cross-origin > w => w.top
 PASS cross-origin > w => w.window
-FAIL same-site > w => w.blur() assert_not_equals: Report not received got disallowed value "timeout"
-FAIL same-site > w => w.close() assert_not_equals: Report not received got disallowed value "timeout"
+PASS same-site > w => w.blur()
+PASS same-site > w => w.close()
 PASS same-site > w => w.closed
-FAIL same-site > w => w.focus() assert_not_equals: Report not received got disallowed value "timeout"
+PASS same-site > w => w.focus()
 PASS same-site > w => w.frames
 FAIL same-site > w => w[0] assert_not_equals: Report not received got disallowed value "timeout"
 PASS same-site > w => w.length
@@ -28,8 +28,8 @@ PASS same-site > w => w.location = "#"
 FAIL same-site > w => w["test"] assert_not_equals: Report not received got disallowed value "timeout"
 PASS same-site > w => w.opener
 PASS same-site > w => w.opener = ""
-FAIL same-site > w => w.postMessage("") assert_not_equals: Report not received got disallowed value "timeout"
-FAIL same-site > w => w.postMessage("", "") assert_not_equals: Report not received got disallowed value "timeout"
+PASS same-site > w => w.postMessage("")
+PASS same-site > w => w.postMessage("", "")
 PASS same-site > w => w.self
 PASS same-site > w => w.top
 FAIL same-site > w => w.window assert_not_equals: Report not received got disallowed value "timeout"