Introduce chrome://flags/#network-prediction-options-for-service-worker

content/browser/service_worker/service_worker_metrics.cc

 // Copyright 2014 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 "content/browser/service_worker/service_worker_metrics.h"
 
 #include <limits>
 #include <string>
 
 #include "base/metrics/histogram_macros.h"
@@ skipping 66 matching lines @@
     case ServiceWorkerMetrics::EventType::PAYMENT_REQUEST:
       return "_PAYMENT_REQUEST";
     case ServiceWorkerMetrics::EventType::BACKGROUND_FETCH_ABORT:
       return "_BACKGROUND_FETCH_ABORT";
     case ServiceWorkerMetrics::EventType::BACKGROUND_FETCH_CLICK:
       return "_BACKGROUND_FETCH_CLICK";
     case ServiceWorkerMetrics::EventType::BACKGROUND_FETCH_FAIL:
       return "_BACKGROUND_FETCH_FAIL";
     case ServiceWorkerMetrics::EventType::BACKGROUND_FETCHED:
       return "_BACKGROUND_FETCHED";
+    case ServiceWorkerMetrics::EventType::PRECONNECT:
+      return "_PRECONNECT";
     case ServiceWorkerMetrics::EventType::NUM_TYPES:
       NOTREACHED() << static_cast<int>(event_type);
   }
   return "_UNKNOWN";
 }
 
 ServiceWorkerMetrics::WorkerPreparationType GetWorkerPreparationType(
     EmbeddedWorkerStatus initial_worker_status,
     ServiceWorkerMetrics::StartSituation start_situation) {
   using Situation = ServiceWorkerMetrics::StartSituation;
@@ skipping 213 matching lines @@
     case EventType::PAYMENT_REQUEST:
       return "Payment Request";
     case EventType::BACKGROUND_FETCH_ABORT:
       return "Background Fetch Abort";
     case EventType::BACKGROUND_FETCH_CLICK:
       return "Background Fetch Click";
     case EventType::BACKGROUND_FETCH_FAIL:
       return "Background Fetch Fail";
     case EventType::BACKGROUND_FETCHED:
       return "Background Fetched";
+    case EventType::PRECONNECT:
+      return "Preconnect";
     case EventType::NUM_TYPES:
       break;
   }
   NOTREACHED() << "Got unexpected event type: " << static_cast<int>(event_type);
   return "error";
 }
 
 ServiceWorkerMetrics::Site ServiceWorkerMetrics::SiteFromURL(const GURL& url) {
   // UIThreadSearchTermsData::GoogleBaseURLValue() returns the google base
   // URL, but not available in content layer.
@@ skipping 327 matching lines @@
       break;
     case EventType::BACKGROUND_FETCH_FAIL:
       UMA_HISTOGRAM_MEDIUM_TIMES("ServiceWorker.BackgroundFetchFailEvent.Time",
                                  time);
       break;
     case EventType::BACKGROUND_FETCHED:
       UMA_HISTOGRAM_MEDIUM_TIMES("ServiceWorker.BackgroundFetchedEvent.Time",
                                  time);
       break;
 
+    case EventType::PRECONNECT:
+    // The predictior preconnection should not be sent as request events.
     case EventType::UNKNOWN:
     case EventType::NUM_TYPES:
       NOTREACHED() << "Invalid event type";
       break;
   }
 }
 
 void ServiceWorkerMetrics::RecordFetchEventStatus(
     bool is_main_resource,
     ServiceWorkerStatusCode status) {
@@ skipping 282 matching lines @@
   constexpr base::TimeDelta kMax = base::TimeDelta::FromDays(1);
   // Set the bucket count to 50 since that is the recommended value for all
   // histograms.
   const int kBucketCount = 50;
 
   UMA_HISTOGRAM_CUSTOM_TIMES("ServiceWorker.Runtime", time, kMin, kMax,
                              kBucketCount);
 }
 
 }  // namespace content