Disable flaky tests on Mac.

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 1234 matching lines @@
   ASSERT_EQ(2, new_browser->tab_strip_model()->count());
   EXPECT_EQ(0, new_browser->tab_strip_model()->active_index());
   EXPECT_EQ(url1_,
             new_browser->tab_strip_model()->GetActiveWebContents()->GetURL());
   EXPECT_EQ(url2_,
             new_browser->tab_strip_model()->GetWebContentsAt(1)->GetURL());
 }
 
 // Regression test for crbug.com/240156. When restoring tabs with a navigation,
 // the navigation should take active tab focus.
+// Flaky on Mac. http://crbug.com/656211.
+#if defined(OS_MACOSX)
+#define MAYBE_RestoreWithNavigateSelectedTab \
+  DISABLED_RestoreWithNavigateSelectedTab
+#else
+#define MAYBE_RestoreWithNavigateSelectedTab RestoreWithNavigateSelectedTab
+#endif
 IN_PROC_BROWSER_TEST_F(SessionRestoreTest, RestoreWithNavigateSelectedTab) {
   // Create 2 tabs.
   ui_test_utils::NavigateToURL(browser(), url1_);
   ui_test_utils::NavigateToURLWithDisposition(
       browser(), url2_, WindowOpenDisposition::NEW_FOREGROUND_TAB,
       ui_test_utils::BROWSER_TEST_WAIT_FOR_NAVIGATION);
 
   // Restore the session by calling chrome::Navigate().
   Browser* new_browser =
       QuitBrowserAndRestoreWithURL(browser(), 3, url3_, true);
@@ skipping 229 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());
     }
   }
 }