Disable PrintPreviewDestinationSettingsTest.RecentDestinationsMissing on Mac

It's flaky.

TBR=rbpotter@chromium.org

BUG=1147205

Change-Id: I8461641ba7380178e272e7a6ab1908de50f9b1c2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2527672Reviewed-by: Mark Pearson <mpearson@chromium.org>
Commit-Queue: Mark Pearson <mpearson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#825664}

chrome/test/data/webui/print_preview/print_preview_ui_browsertest.js

@@ -1461,8 +1461,14 @@ TEST_F('PrintPreviewDestinationSettingsTest', 'RecentDestinations', function() {
   this.runMochaTest(destination_settings_test.TestNames.RecentDestinations);
 });
 
+// Flaky on Mac, see https://crbug.com/1147205
+GEN('#if defined(OS_MAC)');
+GEN('#define MAYBE_RecentDestinationsMissing DISABLED_RecentDestinationsMissing');
+GEN('#else');
+GEN('#define MAYBE_RecentDestinationsMissing RecentDestinationsMissing');
+GEN('#endif');
 TEST_F(
-    'PrintPreviewDestinationSettingsTest', 'RecentDestinationsMissing',
+    'PrintPreviewDestinationSettingsTest', 'MAYBE_RecentDestinationsMissing',
     function() {
       this.runMochaTest(
           destination_settings_test.TestNames.RecentDestinationsMissing);