Add run-webkit-tests support and generate baselines for win8 and win10.

Tools/Scripts/webkitpy/common/system/platforminfo.py

Index: Tools/Scripts/webkitpy/common/system/platforminfo.py
diff --git a/Tools/Scripts/webkitpy/common/system/platforminfo.py b/Tools/Scripts/webkitpy/common/system/platforminfo.py
index e47d5f142ed05db7878779bb5c3cfd52c8641e9c..15e17ee19178d7e3897d98455af0be8fee2734f2 100644
--- a/Tools/Scripts/webkitpy/common/system/platforminfo.py
+++ b/Tools/Scripts/webkitpy/common/system/platforminfo.py
@@ -164,13 +164,23 @@ class PlatformInfo(object):
         return 'trusty' if version not in officially_supported_versions else version
 
     def _determine_win_version(self, win_version_tuple):
+        if win_version_tuple[:2] == (10, 0):
+            return '10'
+        if win_version_tuple[:2] == (6, 3):
+            return '8.1'
+        if win_version_tuple[:2] == (6, 2):
+            return '8'
+        if win_version_tuple[:3] == (6, 1, 7601):
+            return '7sp1'
         if win_version_tuple[:3] == (6, 1, 7600):
             return '7sp0'
         if win_version_tuple[:2] == (6, 0):
             return 'vista'
         if win_version_tuple[:2] == (5, 1):
             return 'xp'
-        assert win_version_tuple[0] > 6 or win_version_tuple[1] >= 1, 'Unrecognized Windows version tuple: "%s"' % (win_version_tuple,)
+        assert (win_version_tuple[0] > 10 or
+                win_version_tuple[0] == 10 and win_version_tuple[1] > 0), (
+            'Unrecognized Windows version tuple: "%s"' % (win_version_tuple,))
         return 'future'
 
     def _win_version_tuple(self, sys_module):