[COOP] Access reporting [12/N] Indexed getter.

Patch [3/N] modified blink windows's binding to call CheckCoopAccess()
whenever a "CrossOrigin" attribute/methods was accessed.

This adds the same check for the indexed getter.

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] https://chromium-review.googlesource.com/c/chromium/src/+/2323250
[12/N] this patch.

Bug: 1090273
Change-Id: Ia0e53c48de1859c734736a599f5050dca3b0b6a6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2339353Reviewed-by: Camille Lamy <clamy@chromium.org>
Reviewed-by: Yuki Shiino <yukishiino@chromium.org>
Commit-Queue: Arthur Sonzogni <arthursonzogni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#796795}

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

@@ -165,7 +165,9 @@ void DOMWindow::postMessage(v8::Isolate* isolate,
                 options, incumbent_window, exception_state);
 }
 
-DOMWindow* DOMWindow::AnonymousIndexedGetter(uint32_t index) const {
+DOMWindow* DOMWindow::AnonymousIndexedGetter(uint32_t index) {
+  ReportCoopAccess(window_proxy_manager_->GetIsolate(), "indexed");
+
   if (!GetFrame())
     return nullptr;
 

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

@@ -109,7 +109,7 @@ class CORE_EXPORT DOMWindow : public EventTargetWithInlineData {
                    ExceptionState&);
 
   // Indexed properties
-  DOMWindow* AnonymousIndexedGetter(uint32_t index) const;
+  DOMWindow* AnonymousIndexedGetter(uint32_t index);
 
   String SanitizedCrossDomainAccessErrorMessage(
       const LocalDOMWindow* accessing_window,

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

-This is a testharness.js-based test.
-FAIL cross-origin > w => w[0] assert_equals: expected 1 but got 0
-PASS cross-origin > w => w[1]
-PASS cross-origin > w => w[-1]
-FAIL same-site > w => w[0] assert_equals: expected 1 but got 0
-PASS same-site > w => w[1]
-PASS same-site > w => w[-1]
-Harness: the test ran to completion.
-