sheriff: disable LocalHistoryZeroSuggestProviderTest on iOS

Bug: 1071877
Change-Id: I3b56e8d59a5383d599105c3d80595222093af460
Tbr: jdonnelly@chromium.org
Cc: ender@google.com
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2159538Reviewed-by: Elly Fong-Jones <ellyjones@chromium.org>
Commit-Queue: Elly Fong-Jones <ellyjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#761127}

components/omnibox/browser/local_history_zero_suggest_provider_unittest.cc

@@ -15,6 +15,7 @@
 #include "base/test/scoped_feature_list.h"
 #include "base/test/task_environment.h"
 #include "base/time/time.h"
+#include "build/build_config.h"
 #include "components/history/core/browser/history_service.h"
 #include "components/history/core/browser/keyword_search_term.h"
 #include "components/history/core/browser/url_database.h"
@@ -275,7 +276,13 @@ TEST_F(LocalHistoryZeroSuggestProviderTest, Incognito) {
 
 // Tests that suggestions are returned only if ZeroSuggestVariant is configured
 // to return local history suggestions in the NTP.
-TEST_F(LocalHistoryZeroSuggestProviderTest, ZeroSuggestVariant) {
+#if defined(OS_IOS)
+// Flaky thread check failure: https://crbug.com/1071877
+#define MAYBE_ZeroSuggestVariant DISABLED_ZeroSuggestVariant
+#else
+#define MAYBE_ZeroSuggestVariant ZeroSuggestVariant
+#endif
+TEST_F(LocalHistoryZeroSuggestProviderTest, MAYBE_ZeroSuggestVariant) {
   LoadURLs({
       {default_search_provider(), "hello world", "&foo=bar", 1},
   });