Disable TabCloseWithCrossSiteBeforeUnloadIframe

TBR=jyasskin@chromium.org
NOTRY=true

Bug: 1010061
Change-Id: I06b679d48413f0b30bc72fe88b199205c6b37429
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1834061Reviewed-by: Xida Chen <xidachen@chromium.org>
Commit-Queue: Xida Chen <xidachen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#701631}

chrome/browser/site_isolation/chrome_site_per_process_browsertest.cc

@@ -1617,8 +1617,9 @@ IN_PROC_BROWSER_TEST_F(ChromeSitePerProcessTest,
 
 // Tests that a cross-site iframe runs its beforeunload handler when closing a
 // tab.  See https://crbug.com/853021.
+// crbug.com/1010061: disabled due to flakiness.
 IN_PROC_BROWSER_TEST_F(ChromeSitePerProcessTest,
-                       TabCloseWithCrossSiteBeforeUnloadIframe) {
+                       DISABLED_TabCloseWithCrossSiteBeforeUnloadIframe) {
   TabStripModel* tab_strip_model = browser()->tab_strip_model();
   content::WebContents* first_web_contents =
       tab_strip_model->GetActiveWebContents();