Move the ContentSuggestions items to a new target

ios/chrome/browser/ui/content_suggestions/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.
 
 source_set("content_suggestions") {
   sources = [
     "content_suggestions_collection_updater.h",
     "content_suggestions_collection_updater.mm",
     "content_suggestions_collection_utils.h",
     "content_suggestions_collection_utils.mm",
     "content_suggestions_commands.h",
     "content_suggestions_data_sink.h",
     "content_suggestions_data_source.h",
     "content_suggestions_image_fetcher.h",
     "content_suggestions_view_controller.h",
     "content_suggestions_view_controller.mm",
   ]
   deps = [
     ":resources",
     "//base",
     "//components/strings",
     "//ios/chrome/app/strings",
     "//ios/chrome/browser/ui",
     "//ios/chrome/browser/ui/collection_view",
     "//ios/chrome/browser/ui/commands",
-    "//ios/chrome/browser/ui/content_suggestions/cells",
+    "//ios/chrome/browser/ui/content_suggestions/cells:cells_ui",
     "//ios/chrome/browser/ui/content_suggestions/identifier",
     "//ios/chrome/browser/ui/favicon:favicon_ui",
     "//ios/chrome/browser/ui/toolbar",
     "//mojo/common:common_custom_types",
     "//ui/base",
     "//url",
   ]
   public_deps = [
     "//ios/third_party/material_components_ios",
   ]
   configs += [ "//build/config/compiler:enable_arc" ]
 }
 
 source_set("unit_tests") {
   testonly = true
   sources = [
     "content_suggestions_collection_updater_unittest.mm",
     "content_suggestions_collection_utils_unittest.mm",
   ]
   deps = [
     ":content_suggestions",
     "//base",
     "//ios/chrome/browser/ui",
     "//ios/chrome/browser/ui/collection_view",
-    "//ios/chrome/browser/ui/content_suggestions/cells",
+    "//ios/chrome/browser/ui/content_suggestions/cells:cells_ui",
     "//ios/chrome/browser/ui/content_suggestions/identifier",
     "//ios/chrome/test/base",
     "//testing/gtest",
     "//third_party/ocmock",
   ]
   configs += [ "//build/config/compiler:enable_arc" ]
 }
 
 bundle_data("resources") {
   sources = [
     "resources/content_suggestions_no_image.png",
     "resources/content_suggestions_no_image@2x.png",
     "resources/content_suggestions_no_image@3x.png",
     "resources/content_suggestions_offline.png",
     "resources/content_suggestions_offline@2x.png",
     "resources/content_suggestions_offline@3x.png",
   ]
   outputs = [
     "{{bundle_resources_dir}}/{{source_file_part}}",
   ]
 }