blink: support mac 10.14 in python libraries

This change:

1) Has platform_info not assert that 10.14 is unsupported
2) Has the web_tests baseline code handle 10.14 (right now the same way it
   handles 10.13)

The second change is almost certainly wrong but this gets run_blinkpy_tests
green locally.

Bug: 892229
Change-Id: Iae1188879f8496aa03fd060ed5590c841515a2c8
Reviewed-on: https://chromium-review.googlesource.com/c/1333567Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Commit-Queue: Elly Fong-Jones <ellyjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#607670}

third_party/blink/tools/blinkpy/common/system/platform_info.py

@@ -147,7 +147,7 @@ class PlatformInfo(object):
 
     def _determine_mac_version(self, mac_version_string):
         minor_release = int(mac_version_string.split('.')[1])
-        assert 9 <= minor_release <= 13, 'Unsupported mac OS version: %s' % mac_version_string
+        assert 9 <= minor_release <= 14, 'Unsupported mac OS version: %s' % mac_version_string
         if minor_release == 9:
             # 10.9 is only partially supported; we pretend we're 10.10.
             return 'mac10.10'

third_party/blink/tools/blinkpy/web_tests/port/mac.py

@@ -37,7 +37,7 @@ _log = logging.getLogger(__name__)
 
 
 class MacPort(base.Port):
-    SUPPORTED_VERSIONS = ('mac10.10', 'mac10.11', 'mac10.12', 'mac10.13', 'retina')
+    SUPPORTED_VERSIONS = ('mac10.10', 'mac10.11', 'mac10.12', 'mac10.13', 'mac10.14', 'retina')
     port_name = 'mac'
 
     # FIXME: We treat Retina (High-DPI) devices as if they are running a
@@ -49,6 +49,7 @@ class MacPort(base.Port):
 
     FALLBACK_PATHS = {}
 
+    FALLBACK_PATHS['mac10.14'] = ['mac']
     FALLBACK_PATHS['mac10.13'] = ['mac']
     FALLBACK_PATHS['mac10.12'] = ['mac-mac10.12'] + FALLBACK_PATHS['mac10.13']
     FALLBACK_PATHS['mac10.11'] = ['mac-mac10.11'] + FALLBACK_PATHS['mac10.12']