[DevTools] Move subtargets functionality from ServiceWorker to Target domain.

third_party/WebKit/Source/devtools/BUILD.gn

 # 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.
 
 import("//build/config/features.gni")
 import("//third_party/WebKit/Source/core/core.gni")
 
 devtools_embedder_scripts = [
   "front_end/devtools.js",
   "front_end/Tests.js",
@@ skipping 113 matching lines @@
   "front_end/sdk/ProfileTreeModel.js",
   "front_end/sdk/RemoteObject.js",
   "front_end/sdk/Resource.js",
   "front_end/sdk/ResourceTreeModel.js",
   "front_end/sdk/RuntimeModel.js",
   "front_end/sdk/Script.js",
   "front_end/sdk/SecurityOriginManager.js",
   "front_end/sdk/ServiceWorkerCacheModel.js",
   "front_end/sdk/ServiceWorkerManager.js",
   "front_end/sdk/SourceMap.js",
+  "front_end/sdk/SubTargetsManager.js",
   "front_end/sdk/Target.js",
   "front_end/sdk/TargetManager.js",
   "front_end/sdk/TracingManager.js",
   "front_end/sdk/TracingModel.js",
   "front_end/sdk/WorkerManager.js",
 ]
 devtools_workspace_js_files = [
   "front_end/workspace/FileManager.js",
   "front_end/workspace/FileSystemMapping.js",
   "front_end/workspace/IsolatedFileSystem.js",
@@ skipping 968 matching lines @@
     deps = [
       ":frontend_protocol_sources",
       ":supported_css_properties",
     ]
     sources = generated_scripts
     outputs = [
       "$resources_out_debug_dir/{{source_file_part}}",
     ]
   }
 }