API changes to support suspending requests

components/offline_pages/background/request_coordinator.h

Index: components/offline_pages/background/request_coordinator.h
diff --git a/components/offline_pages/background/request_coordinator.h b/components/offline_pages/background/request_coordinator.h
index 830d605e57819174e291103bb0f83ca8b3704ba9..1a2f99d3d3c9b15c7c13d1b5ae9205e5ef3f6b5d 100644
--- a/components/offline_pages/background/request_coordinator.h
+++ b/components/offline_pages/background/request_coordinator.h
@@ -55,6 +55,11 @@ class RequestCoordinator : public KeyedService,
     virtual void OnChanged(const SavePageRequest& request) = 0;
   };
 
+  enum class RequestAvailability {
+    AVAILABLE_TO_OFFLINER,
+    DISABLED_TO_OFFLINER,
+  };
+
   // Callback to report when a request was available.
   typedef base::Callback<void(const SavePageRequest& request)>
       RequestPickedCallback;
@@ -71,9 +76,11 @@ class RequestCoordinator : public KeyedService,
   ~RequestCoordinator() override;
 
   // Queues |request| to later load and save when system conditions allow.
-  // Returns true if the page could be queued successfully.
-  bool SavePageLater(
-      const GURL& url, const ClientId& client_id, bool user_reqeusted);
+  // Returns an id if the page could be queued successfully, 0L otherwise.
+  int64_t SavePageLater(const GURL& url,
+                        const ClientId& client_id,
+                        bool user_reqeusted,

[Dmitry Titov, 2016/10/05 22:28:19]

typo: user_reqeusted -> user_requested

[Pete Williamson, 2016/10/05 22:57:46]

Nice catch!  Done.

+                        RequestAvailability availability);

[Dmitry Titov, 2016/10/05 22:28:19]

I'd rather have a "bool do_not_process" or "bool block_offlining".

It makes more sense to casual reader because the request is still created, and
even still causes the notification to pop up - but it is not being offlined yet.

[Pete Williamson, 2016/10/05 22:57:46]

I think that FGorski had the opposite feedback in the design doc, to prefer an
enum here.  I prefer an enum, so I'd like to go with that unless you feel
strongly about this one.

 
   // Callback specifying which request IDs were actually removed.
   typedef base::Callback<void(
@@ -111,6 +118,15 @@ class RequestCoordinator : public KeyedService,
   // is stopped or complete.
   void StopProcessing(Offliner::RequestStatus stop_status);
 
+  // Used to denote that the foreground thread is ready for the offliner
+  // to start work on a previously entered, but unavailable request.
+  void MakeAvailableToOffliner(int64_t request_id);
+
+  // If a request that is unavailable to the offliner is finished elsewhere,
+  // (by the tab helper synchronous download), send a notificaiton that it
+  // succeeded through our notificaiton system.
+  void MarkRequestCompleted(int64_t request_id);
+
   const Scheduler::TriggerConditions GetTriggerConditions(
       const bool user_requested);