Add a virtual test suite for exposed "stable" features

Tools/Scripts/webkitpy/layout_tests/port/chromium.py

 # Copyright (C) 2010 Google Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 # copyright notice, this list of conditions and the following disclaimer
@@ skipping 332 matching lines @@
                              ['--enable-accelerated-overflow-scroll']),
             VirtualTestSuite('virtual/threaded/animations',
                              'animations',
                              ['--enable-threaded-compositing']),
             VirtualTestSuite('virtual/threaded/transitions',
                              'transitions',
                              ['--enable-threaded-compositing']),
             VirtualTestSuite('virtual/web-animations-css/animations',
                              'animations',
                              ['--enable-web-animations-css']),
+            VirtualTestSuite('virtual/stable/webexposed',
+                             'webexposed',
+                             ['--stable-release-mode']),
         ]
 
     #
     # PROTECTED METHODS
     #
     # These routines should only be called by other methods in this file
     # or any subclasses.
     #
 
     def _build_path(self, *comps):
@@ skipping 30 matching lines @@
             # That's fine because, in this case, we must already be running the
             # most up-to-date one.
             except OSError:
                 pass
         return True
 
     def _chromium_baseline_path(self, platform):
         if platform is None:
             platform = self.name()
         return self.path_from_webkit_base('LayoutTests', 'platform', platform)