Reland of Disable flaky SyncSetupWebUITestAsync.VerifySignIn test on Windows.

chrome/browser/ui/webui/sync_setup_browsertest.js

Index: chrome/browser/ui/webui/sync_setup_browsertest.js
diff --git a/chrome/browser/ui/webui/sync_setup_browsertest.js b/chrome/browser/ui/webui/sync_setup_browsertest.js
index 74a9ded5eec455fb064ecec62f25f4108b41cfa8..bcae6e1172c1d78a8681bdec0062ebc2929b3fa2 100644
--- a/chrome/browser/ui/webui/sync_setup_browsertest.js
+++ b/chrome/browser/ui/webui/sync_setup_browsertest.js
@@ -81,12 +81,13 @@
   },
 };
 
-// This test is flaky on Linux bot. See crbug.com/579666
-GEN('#if defined(OS_LINUX)');
+// This test is flaky on Linux bot (crbug.com/579666) and Windows bot
+// (crbug.com/608975).
+GEN('#if defined(OS_LINUX) || defined(OS_WIN)');
 GEN('#define MAYBE_VerifySignIn DISABLED_VerifySignIn');
 GEN('#else');
 GEN('#define MAYBE_VerifySignIn VerifySignIn');
-GEN('#endif  // defined(OS_LINUX)');
+GEN('#endif  // defined(OS_LINUX) || defined(OS_WIN)');
 TEST_F('SyncSetupWebUITestAsync', 'MAYBE_VerifySignIn', function() {
   // Handle SyncSetupStartSignIn by displaying the sync setup dialog, verifying
   // that a confirmation dialog appears, and clicking OK to dismiss the dialog.