Introduce session type parameter to extension features

tools/json_schema_compiler/feature_compiler.py

Index: tools/json_schema_compiler/feature_compiler.py
diff --git a/tools/json_schema_compiler/feature_compiler.py b/tools/json_schema_compiler/feature_compiler.py
index d28880220ec5ccfe3adc560cc9174b4b49afb717..d3525281e53b801ad7a488f041d704525134058f 100644
--- a/tools/json_schema_compiler/feature_compiler.py
+++ b/tools/json_schema_compiler/feature_compiler.py
@@ -189,6 +189,14 @@ FEATURE_GRAMMAR = (
         }
       }
     },
+    'session_types': {
+      list: {
+        'enum_map': {
+          'regular': 'Feature::SESSION_TYPE_REGULAR',
+          'kiosk': 'Feature::SESSION_TYPE_KIOSK',
+        }
+      }
+    },
     'whitelist': {
       list: {'subtype': unicode}
     },