Move common functionality of IOSChromeIOThread to ios/components.

ios/BUILD.gn

 # Copyright 2016 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.
 
 assert(!is_component_build, "component build is unsupported on iOS")
 
 import("//ios/features.gni")
 
 declare_args() {
   # TODO(brettw) bug 684096: Remove these. These are to prevent unused
@@ skipping 33 matching lines @@
       "//ios/chrome/today_extension",
       "//ios/clean/chrome/app:chrome_clean_skeleton",
       "//ios/showcase",
       "//ios/web/shell:ios_web_shell",
       "//ios/web_view/shell:ios_web_view_shell",
 
       # List all the test targets that need to be build on iOS by default.
       "//ios/chrome/test:all_tests",
       "//ios/chrome/test/earl_grey:all_tests",
       "//ios/clean/chrome/test:all_tests",
+      "//ios/components:all_tests",
       "//ios/net:all_tests",
       "//ios/showcase:all_tests",
       "//ios/testing:all_tests",
       "//ios/web:all_tests",
       "//ios/web/shell/test:all_tests",
       "//ios/web_view/shell/test:all_tests",
       "//ios/web_view/test:all_tests",
     ]
   }
 }