[Sheriff]: Disable ClearBrowsingDataAllPlatforms on Mac.

The test CrSettingsClearBrowsingDataV3Test.ClearBrowsingDataAllPlatforms
is flaky on Mac. Disable it.

BUG=1107652
TBR=dpapad@chromium.org

Change-Id: Idbfe7608e8b547c976623d17a8997c954eb2ee4c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2309037Reviewed-by: Karan Bhatia <karandeepb@chromium.org>
Commit-Queue: Karan Bhatia <karandeepb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#790267}

chrome/test/data/webui/settings/cr_settings_v3_browsertest.js

@@ -111,8 +111,14 @@ var CrSettingsClearBrowsingDataV3Test = class extends CrSettingsV3BrowserTest {
   }
 };
 
+// TODO(crbug.com/1107652): Flaky on Mac.
+GEN('#if defined(OS_MACOSX)');
+GEN('#define MAYBE_ClearBrowsingDataAllPlatforms DISABLED_ClearBrowsingDataAllPlatforms');
+GEN('#else');
+GEN('#define MAYBE_ClearBrowsingDataAllPlatforms ClearBrowsingDataAllPlatforms');
+GEN('#endif');
 TEST_F(
-    'CrSettingsClearBrowsingDataV3Test', 'ClearBrowsingDataAllPlatforms',
+    'CrSettingsClearBrowsingDataV3Test', 'MAYBE_ClearBrowsingDataAllPlatforms',
     function() {
       runMochaSuite('ClearBrowsingDataAllPlatforms');
     });