[Offline Pages] Set up the initial prefetching service.

chrome/browser/BUILD.gn

Index: chrome/browser/BUILD.gn
diff --git a/chrome/browser/BUILD.gn b/chrome/browser/BUILD.gn
index 848657c42d538a948b307c0f8db69859afaf5638..3b78e2a35238461222b917cb1e28eec6ed836ba5 100644
--- a/chrome/browser/BUILD.gn
+++ b/chrome/browser/BUILD.gn
@@ -2870,6 +2870,8 @@ split_static_library("browser") {
       "android/offline_pages/offline_page_request_interceptor.h",
       "android/offline_pages/offline_page_request_job.cc",
       "android/offline_pages/offline_page_request_job.h",
+      "android/offline_pages/offline_page_suggestions_observer.cc",
+      "android/offline_pages/offline_page_suggestions_observer.h",
       "android/offline_pages/offline_page_tab_helper.cc",
       "android/offline_pages/offline_page_tab_helper.h",
       "android/offline_pages/offline_page_utils.cc",
@@ -2877,6 +2879,8 @@ split_static_library("browser") {
       "android/offline_pages/offliner_factory.h",
       "android/offline_pages/offliner_helper.cc",
       "android/offline_pages/offliner_helper.h",
+      "android/offline_pages/prefetch_service_factory.cc",
+      "android/offline_pages/prefetch_service_factory.h",
       "android/offline_pages/prerender_adapter.cc",
       "android/offline_pages/prerender_adapter.h",
       "android/offline_pages/prerendering_loader.cc",