Remove old requests from queue, start new requests if any, add test.

components/offline_pages/background/request_coordinator.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COMPONENTS_OFFLINE_PAGES_BACKGROUND_REQUEST_COORDINATOR_H_
 #define COMPONENTS_OFFLINE_PAGES_BACKGROUND_REQUEST_COORDINATOR_H_
 
 #include <memory>
 
 #include "base/callback.h"
@@ skipping 29 matching lines @@
 
   ~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);
 
   // Starts processing of one or more queued save page later requests.
   // Returns whether processing was started and that caller should expect
   // a callback. If processing was already active, returns false.
-  bool StartProcessing(const base::Callback<void(bool)>& callback);
+  bool StartProcessing(const base::Callback<void(bool)> callback);
 
   // Stops the current request processing if active. This is a way for
   // caller to abort processing; otherwise, processing will complete on
   // its own. In either case, the callback will be called when processing
   // is stopped or complete.
   void StopProcessing();
 
+  // Called by the offliner when an offlining request is completed. (and by
+  // tests).
+  void OfflinerDoneCallback(const SavePageRequest& request,

[dewittj, 2016/06/14 16:16:36]

nit: make this private and make the test harness a friend class.

[Pete Williamson, 2016/06/14 21:03:14]

Done.

+                            Offliner::RequestStatus status);
+
+  // A way for tests to set the callback in use when an operation is over.
+  void SetProcessingCallbackForTest(const base::Callback<void(bool)> callback) {
+    scheduler_callback_ = callback;
+  }
+
   // Returns the request queue used for requests.  Coordinator keeps ownership.
   RequestQueue* queue() { return queue_.get(); }
 
   // Return an unowned pointer to the Scheduler.
   Scheduler* scheduler() { return scheduler_.get(); }
 
   // Returns the status of the most recent offlining.
   Offliner::RequestStatus last_offlining_status() {
     return last_offlining_status_;
   }
 
  private:
   void AddRequestResultCallback(RequestQueue::AddRequestResult result,
                                 const SavePageRequest& request);
 
+  void UpdateRequestCallback(RequestQueue::UpdateRequestResult result);
+
   // Callback from the request picker when it has chosen our next request.
   void RequestPicked(const SavePageRequest& request);
 
   // Callback from the request picker when no more requests are in the queue.
   void RequestQueueEmpty();
 
   void SendRequestToOffliner(const SavePageRequest& request);
 
-  void OfflinerDoneCallback(const SavePageRequest& request,
-                            Offliner::RequestStatus status);
+  void TryNextRequest();
 
   // RequestCoordinator takes over ownership of the policy
   std::unique_ptr<OfflinerPolicy> policy_;
   // OfflinerFactory.  Used to create offline pages. Owned.
   std::unique_ptr<OfflinerFactory> factory_;
   // RequestQueue.  Used to store incoming requests. Owned.
   std::unique_ptr<RequestQueue> queue_;
   // Scheduler. Used to request a callback when network is available.  Owned.
   std::unique_ptr<Scheduler> scheduler_;
   // Status of the most recent offlining.
   Offliner::RequestStatus last_offlining_status_;
   // Class to choose which request to schedule next
   std::unique_ptr<RequestPicker> picker_;
+  // Calling this returns to the scheduler across the JNI bridge.
+  base::Callback<void(bool)> scheduler_callback_;
   // Allows us to pass a weak pointer to callbacks.
   base::WeakPtrFactory<RequestCoordinator> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RequestCoordinator);
 };
 
 }  // namespace offline_pages
 
 #endif  // COMPONENTS_OFFLINE_PAGES_BACKGROUND_REQUEST_COORDINATOR_H_