OOR-CORS: CrElementsPolicyPrefIndicatorV3Test.All depends on OOR-CORS

Since CrElementsPolicyPrefIndicatorV3Test.All depends on OOR-CORS
as some other WebUI tests do, we need to flip the OOR-CORS to be
enabled explicitly to run the test.

This is a followup change for the Polymer3 test migration,
https://chromium-review.googlesource.com/c/chromium/src/+/2021335.

Bug: 1042558
Change-Id: I463b82e52af59d403aed0eb79aa1f767f945d5de
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2023712
Commit-Queue: Takashi Toyoshima <toyoshim@chromium.org>
Commit-Queue: Rebekah Potter <rbpotter@chromium.org>
Auto-Submit: Takashi Toyoshima <toyoshim@chromium.org>
Reviewed-by: Rebekah Potter <rbpotter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#735773}

chrome/test/data/webui/cr_elements/cr_elements_v3_browsertest.js

@@ -6,6 +6,7 @@
 
 // Polymer BrowserTest fixture.
 GEN_INCLUDE(['//chrome/test/data/webui/polymer_browser_test_base.js']);
+GEN('#include "services/network/public/cpp/features.h"');
 
 /** Test fixture for shared Polymer 3 elements. */
 // eslint-disable-next-line no-var
@@ -314,6 +315,11 @@ var CrElementsPolicyPrefIndicatorV3Test =
     // Preload a settings URL, so that the test can access settingsPrivate.
     return 'chrome://settings/test_loader.html?module=cr_elements/cr_policy_pref_indicator_tests.m.js';
   }
+
+  /** @override */
+  get featureList() {
+    return {enabled: ['network::features::kOutOfBlinkCors']};
+  }
 };
 
 TEST_F('CrElementsPolicyPrefIndicatorV3Test', 'All', function() {