Add "request" as body parameter

[rbren]

I think when google specifies "request", it's analogous to Swagger's body parameter, e.g.

       "parameters": {
        "userId": {
         "type": "string",
         "description": "The user's email address. The special value me can be used to indicate the authenticated user.",
         "default": "me",
         "required": true,
         "location": "path"
        }
       },
       "parameterOrder": [
        "userId"
       ],
       "request": {
        "$ref": "Draft"
       },
       "response": {
        "$ref": "Draft"
       },