Add sanbdoxed_pages to allow extension/app pages to be served in a sandboxed, unique origin

chrome/browser/extensions/extension_resource_request_policy_apitest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/logging.h"
 #include "chrome/browser/extensions/extension_apitest.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/test/base/ui_test_utils.h"
 #include "content/public/browser/web_contents.h"
@@ skipping 208 matching lines @@
 
 #if defined(OS_MACOSX)
 #define MAYBE_ExtensionAccessibleResources FLAKY_ExtensionAccessibleResources
 #else
 #define MAYBE_ExtensionAccessibleResources ExtensionAccessibleResources
 #endif
 IN_PROC_BROWSER_TEST_F(ExtensionResourceRequestPolicyTest,
                        MAYBE_ExtensionAccessibleResources) {
   ASSERT_TRUE(RunExtensionSubtest("accessible_cer", "main.html")) << message_;
 }
+
+IN_PROC_BROWSER_TEST_F(ExtensionResourceRequestPolicyTest, SandboxedResources) {
+  EXPECT_TRUE(RunExtensionSubtest(
+      "extension_resource_request_policy/sandboxed",
+      "main.html"));
+}