[Sheriff] disabling flaky RecordEngagement_AudioOnly test.

TBR=dalecurtis@chromium.org

Bug: 1020131
Change-Id: Ia35dc8a8543590e45095737ab09aadc10f295d12
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1894002Reviewed-by: Armando Miraglia <armax@chromium.org>
Commit-Queue: Armando Miraglia <armax@chromium.org>
Cr-Commit-Position: refs/heads/master@{#711726}

chrome/browser/media/media_engagement_browsertest.cc

@@ -347,7 +347,14 @@ IN_PROC_BROWSER_TEST_F(MediaEngagementBrowserTest, RecordEngagement) {
   ExpectScores(1, 1, 1, 1);
 }
 
-IN_PROC_BROWSER_TEST_F(MediaEngagementBrowserTest, RecordEngagement_AudioOnly) {
+// Flaky tests on CrOS: http://crbug.com/1020131.
+#if defined(OS_CHROMEOS)
+#define MAYBE_RecordEngagement_AudioOnly DISABLED_RecordEngagement_AudioOnly
+#else
+#define MAYBE_RecordEngagement_AudioOnly RecordEngagement_AudioOnly
+#endif
+IN_PROC_BROWSER_TEST_F(MediaEngagementBrowserTest,
+                       MAYBE_RecordEngagement_AudioOnly) {
   LoadTestPageAndWaitForPlayAndAudible("engagement_test_audio.html", false);
   AdvanceMeaningfulPlaybackTime();
   CloseTab();