Disables all WindowManagerAppTest as they are flakey

mojo/tools/data/apptests

 # This file contains a list of Mojo gtest unit tests.
 #
 # This must be valid Python. It may use the |config| global that will be a
 # mopy.config.Config object, and must set a |tests| global that will contain the
 # list of tests to run.
 #
 # The entries in |tests| are dictionaries of the following form:
 #   {
 #     # Required URL for apptest.
 #     'test': 'mojo:test_app_url',
@@ skipping 59 matching lines @@
       'type': 'gtest_isolated',
       'args': ['--oopif-always-create-new-frame-tree',
                '--enable-html-viewer-test-interface',
                '--use-x11-test-config',
                '--override-use-gl-with-osmesa-for-tests']
     },
     {
       'test': 'mojo:mandoline_browser_apptests',
       'type': 'gtest_isolated',
     },
-    {
-      'test': 'mojo:mash_wm_apptests',
-      'type': 'gtest_isolated',
-      'args': ['--use-x11-test-config',
-               '--override-use-gl-with-osmesa-for-tests']
-    },
+    # TODO(sky): flakey, http://crbug.com/559412 .
+    # {
+    #   'test': 'mojo:mash_wm_apptests',
+    #   'type': 'gtest_isolated',
+    #   'args': ['--use-x11-test-config',
+    #            '--override-use-gl-with-osmesa-for-tests']
+    # },
     # TODO(xhwang): Fix and enable mojo:media_pipeline_integration_apptests.
     # http://crbug.com/501417
     {
       'test': 'mojo:media_apptests',
       'type': 'gtest_isolated',
     },
     {
       'test': 'mojo:sql_apptests',
       'type': 'gtest_isolated',
     },
     {
       'test': 'mojo:web_view_apptests',
       'type': 'gtest_isolated',
       'args': ['--use-x11-test-config',
                '--override-use-gl-with-osmesa-for-tests']
     },
   ]