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

components/offline_pages/core/prefetch/prefetch_service_impl.cc

Index: components/offline_pages/core/prefetch/prefetch_service_impl.cc
diff --git a/components/offline_pages/core/prefetch/prefetch_service_impl.cc b/components/offline_pages/core/prefetch/prefetch_service_impl.cc
index 9e86aba0b591bdd968aaa7e42cfabc1545323a42..f992698fdbc59bbf2dc18d15c57aaa9e2bd6ad58 100644
--- a/components/offline_pages/core/prefetch/prefetch_service_impl.cc
+++ b/components/offline_pages/core/prefetch/prefetch_service_impl.cc
@@ -16,9 +16,20 @@ PrefetchServiceImpl::PrefetchServiceImpl()
 
 PrefetchServiceImpl::~PrefetchServiceImpl() = default;
 
+void PrefetchServiceImpl::ObserveContentSuggestionsService(
+    ntp_snippets::ContentSuggestionsService* service) {

[fgorski, 2017/05/30 18:20:05]

CHECK or DCHECK to ensure we are not passing in the nullptr in production?

[dewittj, 2017/05/30 21:09:18]

Not going to change this code in this patch.

+  suggested_articles_observer_ =
+      base::MakeUnique<SuggestedArticlesObserver>(service, this);
+}
+
+void PrefetchServiceImpl::AddPrefetchGCMHandler(
+    std::unique_ptr<PrefetchGCMHandler> app_handler) {
+  gcm_handler_ = std::move(app_handler);
+}
+
 PrefetchDispatcher* PrefetchServiceImpl::GetDispatcher() {
   return dispatcher_.get();
-};
+}
 
 void PrefetchServiceImpl::Shutdown() {}