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 2cc17e8c24d7aec76fc614223999e3cf2305e5b4..c9b0af9dc040aa8274e735cbf508fad0c78c2fa7 100644
--- a/components/offline_pages/background/request_queue_store.h
+++ b/components/offline_pages/background/request_queue_store.h
@@ -10,11 +10,11 @@
 
 #include "base/callback.h"
 #include "components/offline_pages/background/request_queue.h"
+#include "components/offline_pages/background/save_page_request.h"
+#include "components/offline_pages/offline_page_item.h"
 
 namespace offline_pages {
 
-class SavePageRequest;
-
 // Interface for classes storing save page requests.
 class RequestQueueStore {
  public:
@@ -23,6 +23,8 @@ class RequestQueueStore {
     UPDATED,  // Request was updated successfully.
     FAILED,   // Add or update attempt failed.
   };
+  // TODO(petewil): What if no items were updated?  Maybe this should work more
+  // like DeleteCallback, passing pairs of request_id and status.
 
   typedef base::Callback<void(
       bool /* success */,
@@ -52,6 +54,13 @@ class RequestQueueStore {
   virtual void RemoveRequests(const std::vector<int64_t>& request_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;
 };