Update idlsync.py to pull in dependencies required for chrome api generation.

third_party/chrome/tools/json_schema_compiler/test/objects.json

 [
   {
     "namespace": "objects",
     "types": [],
     "functions": [
       {
         "name": "objectParam",
         "type": "function",
         "description": "Takes an object.",
         "parameters": [
@@ skipping 119 matching lines @@
                 "enum": ["spam", "ham", "eggs"]
               }
             }
           }
         ]
       }
     ]
   }
 ]