[Sync] Enable AndroidSyncSettingsTest

I think original issue was caused by ChromeApplication.onCreate calling
AccountManagerHelper.initializeAccountManagerHelper and discovering instance of
AccountManagerHelper that was set up by test. This issue is addressed by
http://crrev.com/2836373003.

Another issue was that waiting for syncability propagation to ContentResolver
got broken by refactoring http://crrev.com/2778443002. This issue was addressed
by change http://crrev.com/2847663003.

Seems like after these changes test should be passing. I ran it in a loop for
1000 iterations and it passed so I'm enabling the test.

BUG=605567
R=pnoland@chromium.org

Review-Url: https://codereview.chromium.org/2845173003
Cr-Commit-Position: refs/heads/master@{#468098}

components/sync/android/javatests/src/org/chromium/components/sync/AndroidSyncSettingsTest.java

@@ -13,7 +13,6 @@ import android.test.InstrumentationTestCase;
 import org.chromium.base.Callback;
 import org.chromium.base.ThreadUtils;
 import org.chromium.base.test.util.CallbackHelper;
-import org.chromium.base.test.util.DisabledTest;
 import org.chromium.base.test.util.Feature;
 import org.chromium.components.signin.AccountManagerHelper;
 import org.chromium.components.signin.test.util.AccountHolder;
@@ -26,7 +25,6 @@ import java.util.concurrent.TimeoutException;
 /**
  * Tests for AndroidSyncSettings.
  */
-@DisabledTest(message = "https://crbug.com/605567")
 public class AndroidSyncSettingsTest extends InstrumentationTestCase {
     private static class CountingMockSyncContentResolverDelegate
             extends MockSyncContentResolverDelegate {