[Extensions] Re-enable a developer private API unit test.

DeveloperPrivateApiUnitTest.UpdateHostAccessCheck was disabled
for flakiness on ChromeOS, but it's no longer flaky. It passed
3000 iterations on multiple ChromeOS configurations with no
flakes.

Bug: 937355
Change-Id: Ia407ac24e6a79167d6003b3b6e74075490370ded
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2197506Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Commit-Queue: David Bertoni <dbertoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#768485}

chrome/browser/extensions/api/developer_private/developer_private_api_unittest.cc

@@ -1479,14 +1479,7 @@ TEST_F(DeveloperPrivateApiUnitTest, RemoveHostPermission) {
   EXPECT_FALSE(modifier.HasGrantedHostPermission(kMapsGoogleCom));
 }
 
-// This test is flaky on chromeos.
-// https://crbug.com/937355
-#if defined(OS_CHROMEOS)
-#define MAYBE_UpdateHostAccess DISABLED_UpdateHostAccess
-#else
-#define MAYBE_UpdateHostAccess UpdateHostAccess
-#endif
-TEST_F(DeveloperPrivateApiUnitTest, MAYBE_UpdateHostAccess) {
+TEST_F(DeveloperPrivateApiUnitTest, UpdateHostAccess) {
   scoped_refptr<const Extension> extension =
       ExtensionBuilder("test").AddPermission("<all_urls>").Build();
   service()->AddExtension(extension.get());