Move common functionality of IOSChromeIOThread to ios/components.

ios/chrome/browser/BUILD.gn

 # Copyright 2015 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("//build/buildflag_header.gni")
 import("//build/config/features.gni")
 import("//build/config/ios/rules.gni")
 import("//rlz/features/features.gni")
 import("//third_party/protobuf/proto_library.gni")
 
@@ skipping 97 matching lines @@
     "//components/url_formatter",
     "//components/variations",
     "//components/variations/service",
     "//components/version_info",
     "//components/webdata_services",
     "//google_apis",
     "//ios/chrome/app/strings",
     "//ios/chrome/browser/browser_state",
     "//ios/chrome/browser/sync/glue",
     "//ios/chrome/common",
+    "//ios/components/io_thread",
     "//ios/net",
     "//ios/public/provider/chrome/browser",
     "//ios/public/provider/chrome/browser/voice",
     "//ios/web",
     "//ios/web:user_agent",
     "//net",
     "//rlz/features",
     "//url",
   ]
   public_deps = [
@@ skipping 111 matching lines @@
 source_set("browser_internal") {
   configs += [ "//build/config/compiler:enable_arc" ]
   sources = [
     "callback_counter.h",
     "callback_counter.mm",
   ]
   deps = [
     "//base",
   ]
 }