OSX: Try to fix NetworkContextConfigurationBrowserTest.CookiesEnabled.

Looks the CookieStore isn't flushed on browser exit, by default.

BUG=847555

Change-Id: I2596f8ea3d62a5d5e71e0514ba8e7caa6049605d
Reviewed-on: https://chromium-review.googlesource.com/1178803
Commit-Queue: Matt Menke <mmenke@chromium.org>
Reviewed-by: Maks Orlovich <morlovich@chromium.org>
Cr-Commit-Position: refs/heads/master@{#583846}

chrome/browser/net/network_context_configuration_browsertest.cc

@@ -1211,18 +1211,17 @@ IN_PROC_BROWSER_TEST_P(NetworkContextConfigurationBrowserTest,
 
   SetCookie(CookieType::kFirstParty, CookiePersistenceType::kPersistent);
   EXPECT_FALSE(GetCookies(embedded_test_server()->base_url()).empty());
-}
 
-#if defined(OS_MACOSX)
-// Disable the test on Mac OSX since it fails on the bot.
-// (https://crbug.com/847555)
-#define MAYBE_CookiesEnabled DISABLED_CookiesEnabled
-#else
-#define MAYBE_CookiesEnabled CookiesEnabled
-#endif
+  // Flush CookieStore. The CookieStore batches disk operations, so may not have
+  // written the cookie to disk yet.
+  base::RunLoop run_loop;
+  network::mojom::CookieManagerPtr cookie_manager;
+  network_context()->GetCookieManager(mojo::MakeRequest(&cookie_manager));
+  cookie_manager->FlushCookieStore(run_loop.QuitClosure());
+  run_loop.Run();
+}
 
-IN_PROC_BROWSER_TEST_P(NetworkContextConfigurationBrowserTest,
-                       MAYBE_CookiesEnabled) {
+IN_PROC_BROWSER_TEST_P(NetworkContextConfigurationBrowserTest, CookiesEnabled) {
   // Check that the cookie from the first stage of the test was / was not
   // preserved between browser restarts, as expected.
   bool has_cookies = !GetCookies(embedded_test_server()->base_url()).empty();