OOR-CORS: CrSettingsV3BrowserTest inheritances depend on OOR-CORS

Since CrSettingsV3BrowserTest inheritances depend on OOR-CORS
as some other WebUI tests do, we need to flip the OOR-CORS to be
enabled explicitly to run tests.

These failed at linux-blink-cors fyi bots, for instance at
https://ci.chromium.org/p/chromium/builders/ci/linux-blink-cors-rel/1537

Bug: 1042558
Change-Id: I2f01ed89e0793ca04f4c4f325755f42c5b7a1704
Tbr: rbpotter@chromium.org
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2050294Reviewed-by: Takashi Toyoshima <toyoshim@chromium.org>
Commit-Queue: Takashi Toyoshima <toyoshim@chromium.org>
Cr-Commit-Position: refs/heads/master@{#740592}

chrome/test/data/webui/settings/cr_settings_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
@@ -22,6 +23,11 @@ var CrSettingsV3BrowserTest = class extends PolymerTest {
       '//chrome/test/data/webui/mocha_adapter.js',
     ];
   }
+
+  /** @override */
+  get featureList() {
+    return {enabled: ['network::features::kOutOfBlinkCors']};
+  }
 };
 
 // eslint-disable-next-line no-var