[Offline Pages] Feature flag to allow concurrent background loading on svelte

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 <limits>
 #include <utility>
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/logging.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/rand_util.h"
 #include "base/sys_info.h"
 #include "base/time/time.h"
 #include "components/offline_pages/background/offliner_factory.h"
 #include "components/offline_pages/background/offliner_policy.h"
 #include "components/offline_pages/background/request_picker.h"
 #include "components/offline_pages/background/save_page_request.h"
 #include "components/offline_pages/client_policy_controller.h"
+#include "components/offline_pages/offline_page_feature.h"
 #include "components/offline_pages/offline_page_item.h"
 #include "components/offline_pages/offline_page_model.h"
 
 namespace offline_pages {
 
 namespace {
 const bool kUserRequest = true;
 const int kMinDurationSeconds = 1;
 const int kMaxDurationSeconds = 7 * 24 * 60 * 60;  // 7 days
 const int kDurationBuckets = 50;
@@ skipping 510 matching lines @@
       RequestCoordinator::OfflinerImmediateStartStatus::STATUS_COUNT);
 }
 
 RequestCoordinator::OfflinerImmediateStartStatus
 RequestCoordinator::TryImmediateStart() {
   // Make sure not already busy processing.
   if (is_busy_)
     return OfflinerImmediateStartStatus::BUSY;
 
   // Make sure we are not on svelte device to start immediately.
-  if (is_low_end_device_) {
+  if (is_low_end_device_ &&
+      !offline_pages::IsOfflinePagesSvelteConcurrentLoadingEnabled()) {
     DVLOG(2) << "low end device, returning";
     // Let the scheduler know we are done processing and failed due to svelte.
     immediate_schedule_callback_.Run(false);
     return OfflinerImmediateStartStatus::NOT_STARTED_ON_SVELTE;
   }
 
   if (GetConnectionType() ==
              net::NetworkChangeNotifier::ConnectionType::CONNECTION_NONE)
     return OfflinerImmediateStartStatus::NO_CONNECTION;
 
@@ skipping 306 matching lines @@
 
 ClientPolicyController* RequestCoordinator::GetPolicyController() {
   return policy_controller_.get();
 }
 
 void RequestCoordinator::Shutdown() {
   network_quality_estimator_ = nullptr;
 }
 
 }  // namespace offline_pages