Does not crash with unexpected function in debug build.

chrome/common/extensions/api/extension_api.json

 [
   {
     "namespace": "extension",
     "unprivileged": true,
     "types": [
       {
         "id": "MessageSender",
         "type": "object",
         "description": "An object containing information about the script context that sent a message or request.",
         "properties": {
@@ skipping 2470 matching lines @@
             "minimum": 0
           }
         ]
       }
     ],
     "events": []
   },
   {
     "namespace": "experimental.inputUI",
     "nodoc": true,
+    "platforms": ["chromeos touch"],
     "types": [],
     "functions": [
       {
         "name": "register",
         "type": "function",
         "description": "Register the extension, so the extension can receive input method related events.",
         "parameters": [
           { "type": "function",
             "name": "callback",
             "optional": true,
@@ skipping 3307 matching lines @@
           {
             "type": "integer",
             "name": "tabId",
             "description": "The id of the tab that was detached."
           }
         ]
       }
     ]
   }
 ]