[VizHitTesting] Disable...

[VizHitTesting] Disable SitePerProcessHitTestBrowserTest.CrossProcessMouseEnterAndLeaveTest on Linux

The test Site.Cross/0 could not be caused by the suspected change
crrev.com/c/1797092 which only affected Site.Cross/1.

The test is only flaky (timeout) on ChromeOS. Occurences on other
platforms (crash) are no longer present [1]. Disable the test on the
affected OS only.

[1] https://analysis.chromium.org/p/chromium/flake-portal/flakes/occurrences?key=ag9zfmZpbmRpdC1mb3ItbWVybAsSBUZsYWtlImFjaHJvbWl1bUBjb250ZW50X2Jyb3dzZXJ0ZXN0c0BTaXRlUGVyUHJvY2Vzc0hpdFRlc3RCcm93c2VyVGVzdC5Dcm9zc1Byb2Nlc3NNb3VzZUVudGVyQW5kTGVhdmVUZXN0DA&show_all_occurrences=1

Bug: 1006635
Change-Id: I5cc99c678e258846643d933a216575e5268ea9e2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1837712Reviewed-by: Bo <boliu@chromium.org>
Commit-Queue: Yi Gu <yigu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#711369}

content/browser/site_per_process_hit_test_browsertest.cc

@@ -3379,8 +3379,15 @@ IN_PROC_BROWSER_TEST_P(SitePerProcessHitTestBrowserTest,
 // This test verifies that MouseEnter and MouseLeave events fire correctly
 // when the mouse cursor moves between processes.
 // Flaky (timeout): https://crbug.com/1006635.
+#if defined(OS_LINUX)
+#define MAYBE_CrossProcessMouseEnterAndLeaveTest \
+  DISABLED_CrossProcessMouseEnterAndLeaveTest
+#else
+#define MAYBE_CrossProcessMouseEnterAndLeaveTest \
+  CrossProcessMouseEnterAndLeaveTest
+#endif
 IN_PROC_BROWSER_TEST_P(SitePerProcessHitTestBrowserTest,
-                       DISABLED_CrossProcessMouseEnterAndLeaveTest) {
+                       MAYBE_CrossProcessMouseEnterAndLeaveTest) {
   GURL main_url(embedded_test_server()->GetURL(
       "a.com", "/cross_site_iframe_factory.html?a(b,c(d))"));
   EXPECT_TRUE(NavigateToURL(shell(), main_url));