Disable test on Mac due to flaky timeouts.

chrome/browser/sessions/session_restore_browsertest.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <stddef.h>
 
 #include <vector>
 
 #include "base/base_switches.h"
 #include "base/command_line.h"
@@ skipping 1447 matching lines @@
       ASSERT_GT(web_contents()[i - 1]->GetLastActiveTime(),
                 web_contents()[i]->GetLastActiveTime());
     }
   }
 
   // Activate the 2nd tab before the browser closes. This should be persisted in
   // the following test.
   new_browser->tab_strip_model()->ActivateTabAt(1, true);
 }
 
-// PRE_CorrectLoadingOrder is flaky on ChromeOS MSAN. https://crbug.com/582323.
-#if defined (OS_CHROMEOS) && defined(MEMORY_SANITIZER)
+// PRE_CorrectLoadingOrder is flaky on ChromeOS MSAN: https://crbug.com/582323
+// And Mac: https://crbug.com/656687
+#if (defined(OS_CHROMEOS) && defined(MEMORY_SANITIZER)) || defined(OS_MACOSX)
 #define MAYBE_CorrectLoadingOrder DISABLED_CorrectLoadingOrder
 #else
 #define MAYBE_CorrectLoadingOrder CorrectLoadingOrder
 #endif
 IN_PROC_BROWSER_TEST_F(SmartSessionRestoreTest, MAYBE_CorrectLoadingOrder) {
   const int activation_order[] = {4, 2, 5, 0, 3, 1};
   Profile* profile = browser()->profile();
 
   // Close the browser that gets opened automatically so we can track the order
   // of loading of the tabs.
@@ skipping 22 matching lines @@
   // automatically at the start of the test.
   for (size_t i = 1; i < web_contents().size(); i++) {
     GURL expected_url = GURL(kUrls[activation_order[kExpectedNumTabs - i]]);
     ASSERT_EQ(expected_url, web_contents()[i]->GetLastCommittedURL());
     if (i > 0) {
       ASSERT_GT(web_contents()[i - 1]->GetLastActiveTime(),
                 web_contents()[i]->GetLastActiveTime());
     }
   }
 }