Revert "Make protobuf enums canonical for ReadState/WriteState/ConnectState."

extensions/common/api/BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//extensions/generated_extensions_api.gni")
 import("schemas.gni")
 
 # GYP version: extensions/common/api/api.gyp:extensions_api
 generated_extensions_api("api") {
   schemas = true
   bundle = true
 }
 
 # GYP version: extensions/browser/api/api_registration.gyp:extensions_api_registration
 generated_extensions_api("api_registration") {
   impl_dir = "//extensions/browser/api"
   bundle_registration = true
 
   deps = [ ":api" ]
   if (!is_android) {
     deps += [
       "//device/serial",
-      "//extensions/common/api/cast_channel:cast_channel_proto",
       "//skia",
     ]
   }
 }