Tentatively re-enable ScrollBubblingFromOOPIFWithBodyOverflowHidden.

It's possible that the change landed in
https://chromium-review.googlesource.com/c/chromium/src/+/1172723
will resolve the flakiness seen in this test. If not, it would be
nice to get some fresh logs from the bots for debugging purposes.

Bug: 863971
Change-Id: I332b48990e0503e078ccc657d3537c3a6d4f9c7a
Reviewed-on: https://chromium-review.googlesource.com/1210042Reviewed-by: Ken Buchanan <kenrb@chromium.org>
Commit-Queue: James MacLean <wjmaclean@chromium.org>
Cr-Commit-Position: refs/heads/master@{#589179}

content/browser/site_per_process_browsertest.cc

@@ -1836,19 +1836,10 @@ IN_PROC_BROWSER_TEST_F(SitePerProcessBrowserTest,
   scroll_observer->Wait();
 }
 
-#if defined(OS_CHROMEOS) || defined(OS_MACOSX)
-// Flaky: https://crbug.com/836200.
-// Flaky timeouts on Mac: https://crbug.com/863971.
-#define MAYBE_ScrollBubblingFromOOPIFWithBodyOverflowHidden \
-  DISABLED_ScrollBubblingFromOOPIFWithBodyOverflowHidden
-#else
-#define MAYBE_ScrollBubblingFromOOPIFWithBodyOverflowHidden \
-  ScrollBubblingFromOOPIFWithBodyOverflowHidden
-#endif
 // Tests that scrolling bubbles from an oopif if its source body has
 // "overflow:hidden" style.
 IN_PROC_BROWSER_TEST_F(SitePerProcessBrowserTest,
-                       MAYBE_ScrollBubblingFromOOPIFWithBodyOverflowHidden) {
+                       ScrollBubblingFromOOPIFWithBodyOverflowHidden) {
   GURL url_domain_a(embedded_test_server()->GetURL(
       "a.com", "/scrollable_page_with_iframe.html"));
   EXPECT_TRUE(NavigateToURL(shell(), url_domain_a));