Add an API to Pause and Resume background offlining requests.

components/offline_pages/background/request_queue.cc

Index: components/offline_pages/background/request_queue.cc
diff --git a/components/offline_pages/background/request_queue.cc b/components/offline_pages/background/request_queue.cc
index fd4cc54a982b8047e3dad86a2683605782148880..10478ee663b9db0226f006015bf6b98dfaad9ccb 100644
--- a/components/offline_pages/background/request_queue.cc
+++ b/components/offline_pages/background/request_queue.cc
@@ -142,6 +142,14 @@ void RequestQueue::RemoveRequestsByClientId(
                                    base::Bind(RemoveRequestDone, callback));
 }
 
+void RequestQueue::ChangeRequestsState(
+    const std::vector<int64_t>& request_ids,
+    const SavePageRequest::RequestState new_state,
+    const UpdateRequestCallback& callback) {
+  store_->ChangeRequestsState(request_ids, new_state,
+                              base::Bind(UpdateRequestDone, callback));
+}
+
 void RequestQueue::PurgeRequests(const PurgeRequestsCallback& callback) {}
 
 }  // namespace offline_pages