Re-enable BrowserCloseManagerBrowserTest.AddBeforeUnloadDuringClosing.

chrome/browser/lifetime/browser_close_manager_browsertest.cc

Index: chrome/browser/lifetime/browser_close_manager_browsertest.cc
diff --git a/chrome/browser/lifetime/browser_close_manager_browsertest.cc b/chrome/browser/lifetime/browser_close_manager_browsertest.cc
index 9500cc25c466aee834c260b7c02b88705ff393b7..b3a8d62c01026f0b2be909e453347a477020387f 100644
--- a/chrome/browser/lifetime/browser_close_manager_browsertest.cc
+++ b/chrome/browser/lifetime/browser_close_manager_browsertest.cc
@@ -744,14 +744,8 @@ IN_PROC_BROWSER_TEST_P(BrowserCloseManagerBrowserTest,
   EXPECT_TRUE(BrowserList::GetInstance()->empty());
 }
 
-#if defined(OS_MACOSX)
-// Flaky on Mac OSX. See http://crbug.com/700271.
-#define MAYBE_AddBeforeUnloadDuringClosing DISABLED_AddBeforeUnloadDuringClosing
-#else
-#define MAYBE_AddBeforeUnloadDuringClosing AddBeforeUnloadDuringClosing
-#endif
 IN_PROC_BROWSER_TEST_P(BrowserCloseManagerBrowserTest,
-                       MAYBE_AddBeforeUnloadDuringClosing) {
+                       AddBeforeUnloadDuringClosing) {
   // TODO(crbug.com/250305): Currently FastUnloadController is broken.
   // And it is difficult to fix this issue without fixing that one.
   if (GetParam())