[Sheriff] Disable OneMetricReportedOnStartup on CrOS

TBR=treib@chromium.org

Bug: 1000455
Change-Id: Ife8b6a15bc9063fb10316a09b95e7e0de0661a98
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1782847Reviewed-by: Jan Wilken Dörrie <jdoerrie@chromium.org>
Commit-Queue: Jan Wilken Dörrie <jdoerrie@chromium.org>
Cr-Commit-Position: refs/heads/master@{#693083}

chrome/browser/sync/test/integration/single_client_wallet_sync_test.cc

@@ -864,7 +864,14 @@ IN_PROC_BROWSER_TEST_F(SingleClientWalletSyncTest,
   ASSERT_EQ(kDefaultCustomerID, pdm->GetPaymentsCustomerData()->customer_id);
 }
 
-IN_PROC_BROWSER_TEST_F(SingleClientWalletSyncTest, OneMetricReportedOnStartup) {
+// TODO(https://crbug.com/1000455) Flaky on CrOS.
+#if defined(OS_CHROMEOS)
+#define MAYBE_OneMetricReportedOnStartup DISABLED_OneMetricReportedOnStartup
+#else
+#define MAYBE_OneMetricReportedOnStartup OneMetricReportedOnStartup
+#endif
+IN_PROC_BROWSER_TEST_F(SingleClientWalletSyncTest,
+                       MAYBE_OneMetricReportedOnStartup) {
   // Set different data so that we get a full update.
   GetFakeServer()->SetWalletData(
       {CreateSyncWalletCard(/*name=*/"card-1", /*last_four=*/"0001",