Enable disallowdocumentaccess

Allow the ability to restrict same origin documents.
Approved intent to ship https://groups.google.com/a/chromium.org/g/blink-dev/c/TzuPAx9ZOk0/m/5num2KNACAAJ

https://chromestatus.com/feature/5648946183536640

BUG=961448

Change-Id: Ic3996eb5015484fd3d3220b357d5b17d50413d60
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2417099Reviewed-by: Philip Jägenstedt <foolip@chromium.org>
Commit-Queue: Dave Tapuska <dtapuska@chromium.org>
Cr-Commit-Position: refs/heads/master@{#809355}

third_party/blink/renderer/platform/runtime_enabled_features.json5

@@ -690,7 +690,7 @@
     },
     {
       name: "DisallowDocumentAccess",
-      status: "experimental",
+      status: "stable",
     },
     {
       name: "DisplayCutoutAPI",

third_party/blink/web_tests/virtual/stable/webexposed/element-instance-property-listing-expected.txt

@@ -627,6 +627,7 @@ html element iframe
     property contentDocument
     property contentWindow
     property csp
+    property disallowDocumentAccess
     property featurePolicy
     property frameBorder
     property getSVGDocument

third_party/blink/web_tests/virtual/stable/webexposed/global-interface-listing-expected.txt

@@ -2890,6 +2890,7 @@ interface HTMLIFrameElement : HTMLElement
     getter contentDocument
     getter contentWindow
     getter csp
+    getter disallowDocumentAccess
     getter featurePolicy
     getter frameBorder
     getter height
@@ -2911,6 +2912,7 @@ interface HTMLIFrameElement : HTMLElement
     setter allowFullscreen
     setter allowPaymentRequest
     setter csp
+    setter disallowDocumentAccess
     setter frameBorder
     setter height
     setter loading