[Sheriff] Disable CreativeOriginStatusWithThrottlingUnknown on Windows

TBR=cammie@chromium.org

Bug: 1099758
Change-Id: I581ff1493f52d23f4d8018442de11a3b57b86f99
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2270346Reviewed-by: Dominique Fauteux-Chapleau <domfc@chromium.org>
Commit-Queue: Dominique Fauteux-Chapleau <domfc@chromium.org>
Cr-Commit-Position: refs/heads/master@{#783057}

chrome/browser/page_load_metrics/observers/ad_metrics/ads_page_load_metrics_observer_browsertest.cc

@@ -457,10 +457,19 @@ IN_PROC_BROWSER_TEST_F(CreativeOriginAdsPageLoadMetricsObserverBrowserTest,
                            OriginStatusWithThrottling::kUnknownAndUnthrottled);
 }
 
+// Flakily fails on Windows only (crbug.com/1099758)
+#if defined(OS_WIN)
+#define MAYBE_CreativeOriginStatusWithThrottlingUnknown \
+  DISABLED_CreativeOriginStatusWithThrottlingUnknown
+#else
+#define MAYBE_CreativeOriginStatusWithThrottlingUnknown \
+  CreativeOriginStatusWithThrottlingUnknown
+#endif
+
 // Test that a throttled ad with a different origin as the main page is
 // marked as throttled, with indeterminate creative origin status.
 IN_PROC_BROWSER_TEST_F(CreativeOriginAdsPageLoadMetricsObserverBrowserTest,
-                       CreativeOriginStatusWithThrottlingUnknown) {
+                       MAYBE_CreativeOriginStatusWithThrottlingUnknown) {
   TestCreativeOriginStatus(
       MakeFrame("a",
                 MakeFrame("b", MakeFrame("c", nullptr), true /* has_text */,