Add an API to Pause and Resume background offlining requests.

components/offline_pages/background/request_queue_store.h

Index: components/offline_pages/background/request_queue_store.h
diff --git a/components/offline_pages/background/request_queue_store.h b/components/offline_pages/background/request_queue_store.h
index d4a9d3527a3a16e716d87e4e3b0f7435e1a38540..4d97d12938b41163422ccbeb2c47fc0cb3ffba7a 100644
--- a/components/offline_pages/background/request_queue_store.h
+++ b/components/offline_pages/background/request_queue_store.h
@@ -9,6 +9,7 @@
 #include <vector>
 
 #include "base/callback.h"
+#include "components/offline_pages/background/save_page_request.h"
 #include "components/offline_pages/offline_page_item.h"
 
 namespace offline_pages {
@@ -61,6 +62,13 @@ class RequestQueueStore {
   virtual void RemoveRequestsByClientId(const std::vector<ClientId>& client_ids,
                                         const RemoveCallback& callback) = 0;
 
+  // Asynchronously changes the state of requests from the store using their
+  // request id.
+  virtual void ChangeRequestsState(
+      const std::vector<int64_t>& request_ids,
+      const SavePageRequest::RequestState new_state,
+      const UpdateCallback& callback) = 0;
+
   // Resets the store.
   virtual void Reset(const ResetCallback& callback) = 0;
 };