Disable AutofillInteractiveIsolationTest.SimpleCrossSiteFill on ChromeOS

All/AutofillInteractiveIsolationTest.SimpleCrossSiteFill/1 is flaky.
I wasn't able to find a good culprit, so let me disable this so
that owners can figure out.

TBR=estade@chromium.org

Bug: 843935
Change-Id: I3e135fdd51b3b31cfb0fe4af4a031d62984377da
No-Try: True
Reviewed-on: https://chromium-review.googlesource.com/1063418Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Commit-Queue: Kinuko Yasuda <kinuko@chromium.org>
Cr-Commit-Position: refs/heads/master@{#559474}

chrome/browser/autofill/autofill_interactive_uitest.cc

@@ -1807,7 +1807,15 @@ class AutofillInteractiveIsolationTest
   }
 };
 
-IN_PROC_BROWSER_TEST_P(AutofillInteractiveIsolationTest, SimpleCrossSiteFill) {
+// https://crbug.com/843935: Super flaky on ChromeOS.
+#if defined(OS_CHROMEOS)
+#define MAYBE_SimpleCrossSiteFill DISABLED_SimpleCrossSiteFill
+#else
+#define MAYBE_SimpleCrossSiteFill SimpleCrossSiteFill
+#endif
+
+IN_PROC_BROWSER_TEST_P(AutofillInteractiveIsolationTest,
+                       MAYBE_SimpleCrossSiteFill) {
   CreateTestProfile();
 
   // Main frame is on a.com, iframe is on b.com.