[Signin][Android] Re-enable FirstRunTest

Enables FirstRunTest that was fixed in https://crrev.com/c/2450291.
Enabling is done in a separate CL to simplify the revert in case these
tests are still flaky.

Bug: 616456
Change-Id: I289ccf035a22835b38917680fd74fb8ce9b3e761
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2487104
Commit-Queue: Boris Sazonov <bsazonov@chromium.org>
Reviewed-by: Marc Treib <treib@chromium.org>
Cr-Commit-Position: refs/heads/master@{#818931}

chrome/android/javatests/src/org/chromium/chrome/browser/sync/FirstRunTest.java

@@ -22,7 +22,6 @@ import org.junit.runner.RunWith;
 
 import org.chromium.base.CommandLine;
 import org.chromium.base.test.util.CallbackHelper;
-import org.chromium.base.test.util.DisabledTest;
 import org.chromium.base.test.util.Feature;
 import org.chromium.chrome.browser.SyncFirstSetupCompleteSource;
 import org.chromium.chrome.browser.document.ChromeLauncherActivity;
@@ -114,7 +113,6 @@ public class FirstRunTest {
     @Test
     @LargeTest
     @Feature({"Sync"})
-    @DisabledTest(message = "https://crbug.com/616456")
     public void testSignIn() {
         Account testAccount = mSyncTestRule.addTestAccount();
         Assert.assertNull(mSyncTestRule.getCurrentSignedInAccount());
@@ -130,7 +128,6 @@ public class FirstRunTest {
     @Test
     @LargeTest
     @Feature({"Sync"})
-    @DisabledTest(message = "https://crbug.com/616456")
     public void testSignInWithOpenSettings() {
         final Account testAccount = mSyncTestRule.addTestAccount();
         final SettingsActivity settingsActivity =
@@ -163,7 +160,6 @@ public class FirstRunTest {
     @Test
     @LargeTest
     @Feature({"Sync"})
-    @DisabledTest(message = "https://crbug.com/616456")
     public void testNoSignIn() {
         mSyncTestRule.addTestAccount();
         Assert.assertFalse(SyncTestUtil.isSyncRequested());