[OfflinePages] Clear busy flag in StopPrerendering() in Request Coordinator.

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/callback.h"
@@ skipping 111 matching lines @@
                                      active_request_->client_id()));
   }
 
   // Stopping offliner means it will not call callback.
   last_offlining_status_ =
       Offliner::RequestStatus::REQUEST_COORDINATOR_CANCELED;
 
   if (active_request_) {
     RecordOfflinerResultUMA(active_request_->client_id(),
                             last_offlining_status_);
+    is_busy_ = false;
     active_request_.reset();
   }
 
 }
 
 bool RequestCoordinator::CancelActiveRequestIfItMatches(
     const std::vector<int64_t>& request_ids) {
   // If we have a request in progress and need to cancel it, call the
   // pre-renderer to cancel.  TODO Make sure we remove any page created by the
   // prerenderer if it doesn't get the cancel in time.
@@ skipping 306 matching lines @@
   FOR_EACH_OBSERVER(Observer, observers_, OnChanged(request));
 }
 
 void RequestCoordinator::GetOffliner() {
   if (!offliner_) {
     offliner_ = factory_->GetOffliner(policy_.get());
   }
 }
 
 }  // namespace offline_pages