Suggestions UI - Add Article items

ios/chrome/browser/ui/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("suggestions") {
   configs += [ "//build/config/compiler:enable_arc" ]
   sources = [
+    "suggestions_article_item.h",
+    "suggestions_article_item.mm",
     "suggestions_collection_updater.h",
     "suggestions_collection_updater.mm",
     "suggestions_commands.h",
     "suggestions_item.h",
     "suggestions_item.mm",
     "suggestions_item_actions.h",
     "suggestions_view_controller.h",
     "suggestions_view_controller.mm",
   ]
   deps = [
     "//base",
     "//ios/chrome/browser/ui",
     "//ios/chrome/browser/ui/collection_view",
     "//ios/third_party/material_roboto_font_loader_ios",
   ]
   public_deps = [
     "//ios/third_party/material_components_ios",
   ]
 }
+
+source_set("unit_tests") {
+  testonly = true
+  sources = [
+    "suggestions_article_item_unittest.mm",
+  ]
+  deps = [
+    ":suggestions",
+    "//ios/chrome/browser/ui/collection_view",
+    "//testing/gtest",
+  ]
+}