Add an API to Pause and Resume background offlining requests.

components/offline_pages/background/request_queue_in_memory_store.h

Index: components/offline_pages/background/request_queue_in_memory_store.h
diff --git a/components/offline_pages/background/request_queue_in_memory_store.h b/components/offline_pages/background/request_queue_in_memory_store.h
index cc02921c6d94bb2b0d778e32c6bd691b92be432d..e16e388f0c021e43bd8654dbaf7c865d72099c3e 100644
--- a/components/offline_pages/background/request_queue_in_memory_store.h
+++ b/components/offline_pages/background/request_queue_in_memory_store.h
@@ -11,11 +11,10 @@
 
 #include "base/macros.h"
 #include "components/offline_pages/background/request_queue_store.h"
+#include "components/offline_pages/background/save_page_request.h"
 
 namespace offline_pages {
 
-class SavePageRequest;
-
 // Interface for classes storing save page requests.
 class RequestQueueInMemoryStore : public RequestQueueStore {
  public:
@@ -34,6 +33,11 @@ class RequestQueueInMemoryStore : public RequestQueueStore {
   // result will be true, but the count of deleted pages will be 0.
   void RemoveRequestsByClientId(const std::vector<ClientId>& client_ids,
                                 const RemoveCallback& callback) override;
+  // Set the state of associated requests to |new_state|.
+  void ChangeRequestsState(const std::vector<int64_t>& request_ids,
+                           const SavePageRequest::RequestState new_state,
+                           const UpdateCallback& callback) override;
+
   void Reset(const ResetCallback& callback) override;
 
  private: