[Offline Pages] Add a GCMAppHandler for offline page prefetch.

chrome/browser/profiles/chrome_browser_main_extra_parts_profiles.cc

Index: chrome/browser/profiles/chrome_browser_main_extra_parts_profiles.cc
diff --git a/chrome/browser/profiles/chrome_browser_main_extra_parts_profiles.cc b/chrome/browser/profiles/chrome_browser_main_extra_parts_profiles.cc
index bf641e67262e7708cf179e426dc9c80c88a574e5..47c3cbd88492a18edf1253038ec08343de0c5f86 100644
--- a/chrome/browser/profiles/chrome_browser_main_extra_parts_profiles.cc
+++ b/chrome/browser/profiles/chrome_browser_main_extra_parts_profiles.cc
@@ -75,6 +75,7 @@
 #include "chrome/browser/undo/bookmark_undo_service_factory.h"
 #include "chrome/browser/web_data_service_factory.h"
 #include "chrome/common/features.h"
+#include "components/offline_pages/features/features.h"
 #include "components/spellcheck/spellcheck_build_features.h"
 #include "extensions/features/features.h"
 #include "ppapi/features/features.h"
@@ -149,6 +150,10 @@
 #include "chrome/browser/printing/cloud_print/privet_notifications_factory.h"
 #endif
 
+#if BUILDFLAG(ENABLE_OFFLINE_PAGES)
+#include "chrome/browser/offline_pages/prefetch/prefetch_service_factory.h"
+#endif
+
 namespace chrome {
 
 void AddProfilesExtraParts(ChromeBrowserMainParts* main_parts) {
@@ -254,6 +259,9 @@ EnsureBrowserContextKeyedServiceFactoriesBuilt() {
 #if BUILDFLAG(ENABLE_SERVICE_DISCOVERY)
   cloud_print::PrivetNotificationServiceFactory::GetInstance();
 #endif
+#if BUILDFLAG(ENABLE_OFFLINE_PAGES)
+  offline_pages::PrefetchServiceFactory::GetInstance();
+#endif
 #if BUILDFLAG(ENABLE_SUPERVISED_USERS)
 #if defined(OS_CHROMEOS)
   chromeos::SupervisedUserPasswordServiceFactory::GetInstance();