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

testing/variations/fieldtrial_testing_config.json

 {
     "AlternateComponentUrls": [
         {
             "platforms": [
                 "android",
                 "chromeos",
                 "ios",
                 "linux",
                 "mac",
                 "win"
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             "experiments": [
                 {
                     "name": "Enabled",
                     "enable_features": [
                         "PrioritySupportedRequestsDelayable"
                     ]
                 }
             ]
         }
     ],
+    "NetworkPredictionOptionsForServiceWorker": [
+        {
+            "platforms": [
+                "chromeos",
+                "linux",
+                "mac",
+                "win",
+                "android"
+            ],
+            "experiments": [
+                {
+                    "name": "PreconnectOnly"
+                },
+                {
+                    "name": "StartServiceWorkerAndPreconnect"
+                },
+                {
+                    "name": "StartServiceWorkerAndDeferPreconnect"
+                },
+                {
+                    "name": "StartServiceWorkerOnly"
+                }
+            ]
+        }
+    ],
     "NetworkQualityEstimator": [
         {
             "platforms": [
                 "android",
                 "win"
             ],
             "experiments": [
                 {
                     "name": "Enabled",
                     "params": {
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                 {
                     "name": "Enabled",
                     "enable_features": [
                         "use-new-media-cache"
                     ]
                 }
             ]
         }
     ]
 }