[Sheriff] Disable TaskManagerExistingPrintPreview for being flaky on Mac.

chrome/browser/ui/webui/print_preview/print_preview_ui_browsertest.cc

 // Copyright (c) 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 "base/command_line.h"
 #include "base/prefs/pref_service.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/app/chrome_command_ids.h"
 #include "chrome/browser/content_settings/host_content_settings_map.h"
 #include "chrome/browser/profiles/profile.h"
@@ skipping 85 matching lines @@
 
   // Create the print preview dialog.
   Print();
 
   ASSERT_NO_FATAL_FAILURE(WaitForTaskManagerRows(1, MatchAboutBlankTab()));
   ASSERT_NO_FATAL_FAILURE(WaitForTaskManagerRows(1, MatchAnyTab()));
   ASSERT_NO_FATAL_FAILURE(WaitForTaskManagerRows(1, MatchAnyPrint()));
   ASSERT_NO_FATAL_FAILURE(WaitForTaskManagerRows(1, MatchPrint("about:blank")));
 }
 
-IN_PROC_BROWSER_TEST_F(PrintPreviewTest, TaskManagerExistingPrintPreview) {
+// Disable the test for mac as it started being flaky, see http://crbug/367665.
+#if defined(OS_MACOSX) && !defined(OS_IOS)
+#define MAYBE_TaskManagerExistingPrintPreview DISABLED_TaskManagerExistingPrintPreview
+#else
+#define MAYBE_TaskManagerExistingPrintPreview TaskManagerExistingPrintPreview
+#endif
+IN_PROC_BROWSER_TEST_F(PrintPreviewTest,
+                       MAYBE_TaskManagerExistingPrintPreview) {
   // Create the print preview dialog.
   Print();
 
   chrome::ShowTaskManager(browser());  // Show task manager AFTER print dialog.
 
   ASSERT_NO_FATAL_FAILURE(WaitForTaskManagerRows(1, MatchAboutBlankTab()));
   ASSERT_NO_FATAL_FAILURE(WaitForTaskManagerRows(1, MatchAnyTab()));
   ASSERT_NO_FATAL_FAILURE(WaitForTaskManagerRows(1, MatchAnyPrint()));
   ASSERT_NO_FATAL_FAILURE(WaitForTaskManagerRows(1, MatchPrint("about:blank")));
 }
@@ skipping 72 matching lines @@
   browser()->tab_strip_model()->ActivateTabAt(0, true);
 
   // Navigate main tab to hide print preview.
   ui_test_utils::NavigateToURL(browser(), GURL("about:blank"));
 
   browser()->tab_strip_model()->ActivateTabAt(1, true);
 }
 #endif
 
 }  // namespace