JSON Schema Compiler supports Enums as types.

tools/json_schema_compiler/test/enums.json

Index: tools/json_schema_compiler/test/enums.json
diff --git a/tools/json_schema_compiler/test/enums.json b/tools/json_schema_compiler/test/enums.json
index ae6be004d84a5facc09f945ce79bad0acb5459d0..48c2c980ddf5526168c9be83dd5a948c8b81a2ea 100644
--- a/tools/json_schema_compiler/test/enums.json
+++ b/tools/json_schema_compiler/test/enums.json
@@ -3,6 +3,10 @@
     "namespace": "enums",
     "types": [
       {
+        "id": "Enumeration",
+        "enum": ["none", "one", "two", "three"]
+      },
+      {
         "id": "EnumType",
         "type": "object",
         "properties": {
@@ -13,6 +17,19 @@
         }
       },
       {
+        "id": "HasEnumeration",
+        "type": "object",
+        "properties": {
+          "enumeration": {
+            "$ref": "Enumeration"
+          },
+          "optional_enumeration": {
+            "$ref": "Enumeration",
+            "optional": true
+          }
+        }
+      },
+      {
         "id": "OptionalEnumType",
         "type": "object",
         "properties": {
@@ -43,6 +60,22 @@
         ]
       },
       {
+        "name": "takesEnumAsType",
+        "type": "function",
+        "description": "Takes an enum type as its parameter.",
+        "parameters": [
+          {
+            "name": "enumeration",
+            "$ref": "Enumeration"
+          },
+          {
+            "name": "callback",
+            "type": "function",
+            "parameters": []
+          }
+        ]
+      },
+      {
         "name": "returnsEnum",
         "type": "function",
         "description": "Returns an enum through the callback",
@@ -61,6 +94,23 @@
         ]
       },
       {
+        "name": "returnsEnumAsType",
+        "type": "function",
+        "description": "Returns an enum through the callback",
+        "parameters": [
+          {
+            "name": "callback",
+            "type": "function",
+            "parameters": [
+              {
+                "name": "enumeration",
+                "$ref": "Enumeration"
+              }
+            ]
+          }
+        ]
+      },
+      {
         "name": "returnsTwoEnums",
         "type": "function",
         "description": "Returns two enums through the callback",