ipcMain validation (#147071)

* first cut ipc validation

* clean up

* comment

build/lib/layersChecker.js

@@ -191,6 +191,9 @@ const RULES = [
             'Event',
             'Request'
         ],
+        disallowedTypes: [
+            'ipcMain' // not allowed, use validatedIpcMain instead
+        ],
         disallowedDefinitions: [
             'lib.dom.d.ts' // no DOM
         ]