Add CWVUserContentController which enables injecting JavaScripts.

ios/web_view/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.
 
 import("//build/config/ios/ios_sdk.gni")
 import("//build/config/ios/rules.gni")
 import("//tools/grit/repack.gni")
 
 config("config") {
   include_dirs = [
@@ skipping 12 matching lines @@
 
   public_headers = [
     "public/criwv_translate_manager.h",
     "public/cwv.h",
     "public/cwv_delegate.h",
     "public/cwv_html_element.h",
     "public/cwv_navigation_action.h",
     "public/cwv_navigation_delegate.h",
     "public/cwv_translate_delegate.h",
     "public/cwv_ui_delegate.h",
+    "public/cwv_user_content_controller.h",
+    "public/cwv_user_script.h",
     "public/cwv_web_view.h",
     "public/cwv_web_view_configuration.h",
   ]
 
   deps = [
     ":packed_resources",
     "//base",
     "//components/infobars/core",
     "//components/keyed_service/core",
     "//components/keyed_service/ios",
@@ skipping 42 matching lines @@
   public_deps = [
     ":repack_resources",
   ]
   sources = [
     "$target_gen_dir/web_view_resources.pak",
   ]
   outputs = [
     "{{bundle_resources_dir}}/{{source_file_part}}",
   ]
 }