Add unit tests for the Background Scheduler.

components/offline_pages/background/request_coordinator.cc

 // 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.
 
 #include "components/offline_pages/background/request_coordinator.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/logging.h"
@@ skipping 78 matching lines @@
                  weak_ptr_factory_.GetWeakPtr()),
       base::Bind(&RequestCoordinator::RequestQueueEmpty,
                  weak_ptr_factory_.GetWeakPtr()));
   return false;
 }
 
 void RequestCoordinator::StopProcessing() {
 }
 
 void RequestCoordinator::SendRequestToOffliner(const SavePageRequest& request) {
+  // TODO(petewil): Ensure only one offliner at a time is used.
   // TODO(petewil): When we have multiple offliners, we need to pick one.
   Offliner* offliner = factory_->GetOffliner(policy_.get());
   if (!offliner) {
     DVLOG(0) << "Unable to create Offliner. "
              << "Cannot background offline page.";
     return;
   }
 
   // Start the load and save process in the offliner (Async).
   offliner->LoadAndSave(request,
                         base::Bind(&RequestCoordinator::OfflinerDoneCallback,
                                    weak_ptr_factory_.GetWeakPtr()));
 }
 
 void RequestCoordinator::OfflinerDoneCallback(const SavePageRequest& request,
                                               Offliner::RequestStatus status) {
   DVLOG(2) << "offliner finished, saved: "
            << (status == Offliner::RequestStatus::SAVED) << ", "
            << __FUNCTION__;
   last_offlining_status_ = status;
 
   // TODO(petewil): Check time budget.  Start a request if we have time, return
   // to the scheduler if we are out of time.
 
   // TODO(petewil): If the request succeeded, remove it from the Queue.
 }
 
 }  // namespace offline_pages