[Sheriff] Disable ChromeVoxNavigateAndSelect on CrOS - flaky.

chrome/browser/chromeos/accessibility/spoken_feedback_browsertest.cc

Index: chrome/browser/chromeos/accessibility/spoken_feedback_browsertest.cc
diff --git a/chrome/browser/chromeos/accessibility/spoken_feedback_browsertest.cc b/chrome/browser/chromeos/accessibility/spoken_feedback_browsertest.cc
index 8b3f5aebeb5c7000f67c1041be14e1bfe1b41a75..eb48c3779e8e2e9ac90dab8e240acf89e9d2dfda 100644
--- a/chrome/browser/chromeos/accessibility/spoken_feedback_browsertest.cc
+++ b/chrome/browser/chromeos/accessibility/spoken_feedback_browsertest.cc
@@ -532,8 +532,9 @@ IN_PROC_BROWSER_TEST_P(SpokenFeedbackTest, MAYBE_ChromeVoxShiftSearch) {
   }
 }
 
-#if defined(MEMORY_SANITIZER)
+#if defined(MEMORY_SANITIZER) || defined(OS_CHROMEOS)
 // Fails under MemorySanitizer: http://crbug.com/472125
+// TODO(crbug.com/721475): Flaky on CrOS.
 #define MAYBE_ChromeVoxNavigateAndSelect DISABLED_ChromeVoxNavigateAndSelect
 #else
 #define MAYBE_ChromeVoxNavigateAndSelect ChromeVoxNavigateAndSelect