Add webkitpy platform support for Mac 10.10 Yosemite.

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

Index: Tools/Scripts/webkitpy/layout_tests/port/mac_unittest.py
diff --git a/Tools/Scripts/webkitpy/layout_tests/port/mac_unittest.py b/Tools/Scripts/webkitpy/layout_tests/port/mac_unittest.py
index aa5653b06fcb5a00f3a05a0b5e8a80f435cb4f09..cebb9f258742a8df38d41e18b161c261143b5cd2 100644
--- a/Tools/Scripts/webkitpy/layout_tests/port/mac_unittest.py
+++ b/Tools/Scripts/webkitpy/layout_tests/port/mac_unittest.py
@@ -45,7 +45,7 @@ class MacPortTest(port_testcase.PortTestCase):
         self.assertEqual(expected, port.name())
 
     def test_versions(self):
-        self.assertTrue(self.make_port().name() in ('mac-snowleopard', 'mac-lion', 'mac-mountainlion', 'mac-mavericks'))
+        self.assertTrue(self.make_port().name() in ('mac-snowleopard', 'mac-lion', 'mac-mountainlion', 'mac-mavericks', 'mac-yosemite'))
 
         self.assert_name(None, 'snowleopard', 'mac-snowleopard')
         self.assert_name('mac', 'snowleopard', 'mac-snowleopard')
@@ -55,7 +55,8 @@ class MacPortTest(port_testcase.PortTestCase):
         self.assert_name(None, 'lion', 'mac-lion')
         self.assert_name(None, 'mountainlion', 'mac-mountainlion')
         self.assert_name(None, 'mavericks', 'mac-mavericks')
-        self.assert_name(None, 'future', 'mac-mavericks')
+        self.assert_name(None, 'yosemite', 'mac-yosemite')
+        self.assert_name(None, 'future', 'mac-yosemite')
 
         self.assert_name('mac', 'lion', 'mac-lion')
         self.assertRaises(AssertionError, self.assert_name, None, 'tiger', 'should-raise-assertion-so-this-value-does-not-matter')
@@ -71,6 +72,9 @@ class MacPortTest(port_testcase.PortTestCase):
         self.assertEqual(port.baseline_path(), port._webkit_baseline_path('mac-mountainlion'))
 
         port = self.make_port(port_name='mac-mavericks')
+        self.assertEqual(port.baseline_path(), port._webkit_baseline_path('mac-mavericks'))
+
+        port = self.make_port(port_name='mac-yosemite')
         self.assertEqual(port.baseline_path(), port._webkit_baseline_path('mac'))
 
     def test_operating_system(self):