Disable flaky test ui.WindowControl.

Bug: 1162346
Change-Id: Ifb876edf670d0346d3b38469349bd0d80028671c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2602847Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Commit-Queue: Hui Yingst <nigi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#839673}

chromeos/BUILD.gn

@@ -269,6 +269,9 @@ if (is_chromeos_device) {
   tast_test("chrome_all_tast_tests") {
     # To disable a specific test, add it the following list and cite a bug.
     tast_disabled_tests = [
+      # crbug.com/1162346
+      "ui.WindowControl",
+
       # crbug.com/1115622
       "ui.ChromeLoginGAIA",