Re-enable SiteIsolationPolicyBrowserTest.NoPolicyNoTrialsFlags.

not_site_per_process_browser_tests step has been removed by r581059 back
in August - therefore the original reason for disabling
SiteIsolationPolicyBrowserTest.NoPolicyNoTrialsFlags test is gone and
the test can be re-enabled everywhere.

Bug: 833423
Change-Id: If4d197202c18c277e80d6e37760c2e0bb6c4c622
Reviewed-on: https://chromium-review.googlesource.com/c/1315359Reviewed-by: Julian Pastarmov <pastarmovj@chromium.org>
Commit-Queue: Łukasz Anforowicz <lukasza@chromium.org>
Cr-Commit-Position: refs/heads/master@{#605415}

chrome/browser/policy/site_isolation_policy_browsertest.cc

@@ -217,15 +217,9 @@ IN_PROC_BROWSER_TEST_F(SitePerProcessPolicyBrowserTestFieldTrialTest, Simple) {
   CheckExpectations(expectations, arraysize(expectations));
 }
 
-// https://crbug.com/833423: The test is incompatible with the
-// not_site_per_process_browser_tests step on the trybots.
-#if defined(OS_LINUX)
-#define MAYBE_NoPolicyNoTrialsFlags DISABLED_NoPolicyNoTrialsFlags
-#else
-#define MAYBE_NoPolicyNoTrialsFlags NoPolicyNoTrialsFlags
-#endif
-IN_PROC_BROWSER_TEST_F(SiteIsolationPolicyBrowserTest,
-                       MAYBE_NoPolicyNoTrialsFlags) {
+IN_PROC_BROWSER_TEST_F(SiteIsolationPolicyBrowserTest, NoPolicyNoTrialsFlags) {
+  // The switch to disable Site Isolation should be missing by default (i.e.
+  // without an explicit enterprise policy).
   ASSERT_FALSE(base::CommandLine::ForCurrentProcess()->HasSwitch(
       switches::kDisableSiteIsolation));
 }