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 9b04a7965a5abc310b334cd6d00b861396fbf913..9e0b8fb6883c2a1116e1936c8568e4cc155780c3 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': 'FeatureSessionType::REGULAR',
+          'kiosk': 'FeatureSessionType::KIOSK',
+        }
+      }
+    },
     'whitelist': {
       list: {'subtype': unicode}
     },