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 4aa68f3a5921f1edb7980a903fb3cdd99d4ece00..efab139785b10dd8cd9bd8a43856cd75a1e9f88a 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:
@@ -26,11 +25,17 @@ class RequestQueueInMemoryStore : public RequestQueueStore {
   void GetRequests(const GetRequestsCallback& callback) override;
   void AddOrUpdateRequest(const SavePageRequest& request,
                           const UpdateCallback& callback) override;
+
   // Remove requests by request ID.  In case the |request_ids| is empty, the
   // result will be true, but the count of deleted pages will be 0.
   void RemoveRequests(const std::vector<int64_t>& request_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: