Adding an IO Data and keyed service to previews/

chrome/browser/BUILD.gn

Index: chrome/browser/BUILD.gn
diff --git a/chrome/browser/BUILD.gn b/chrome/browser/BUILD.gn
index 2a8c743c9d888cb740225ecd8d541edce8cdaae2..90b12cd69bdeef466a7e48ba32170b805132e8a0 100644
--- a/chrome/browser/BUILD.gn
+++ b/chrome/browser/BUILD.gn
@@ -846,20 +846,24 @@ split_static_library("browser") {
     "prerender/prerender_message_filter.cc",
     "prerender/prerender_message_filter.h",
     "prerender/prerender_origin.cc",
     "prerender/prerender_origin.h",
     "prerender/prerender_resource_throttle.cc",
     "prerender/prerender_resource_throttle.h",
     "prerender/prerender_tab_helper.cc",
     "prerender/prerender_tab_helper.h",
     "prerender/prerender_util.cc",
     "prerender/prerender_util.h",
+    "previews/previews_service.cc",
+    "previews/previews_service.h",
+    "previews/previews_service_factory.cc",
+    "previews/previews_service_factory.h",
     "process_resource_usage.cc",
     "process_resource_usage.h",
     "process_singleton.h",
     "process_singleton_win.cc",
     "profiles/avatar_menu_actions.h",
     "profiles/bookmark_model_loaded_observer.cc",
     "profiles/bookmark_model_loaded_observer.h",
     "profiles/chrome_browser_main_extra_parts_profiles.cc",
     "profiles/chrome_browser_main_extra_parts_profiles.h",
     "profiles/chrome_version_service.cc",