ServiceWorker: Implement StartWorker by using mojo

content/common/service_worker/embedded_worker.mojom

+// 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.
+
+module content.mojom;
+
+import "content/public/common/web_preferences.mojom";
+import "services/shell/public/interfaces/interface_provider.mojom";
+import "url/mojo/url.mojom";
+
+struct EmbeddedWorkerSettings {
+  V8CacheOptions v8_cache_options;
+  bool data_saver_enabled;
+};
+
+struct EmbeddedWorkerStartWorkerParams {
+  int32 embedded_worker_id;
+  int64 service_worker_version_id;
+  url.mojom.Url scope;
+  url.mojom.Url script_url;
+  int32 worker_devtools_agent_route_id;
+  bool pause_after_download;
+  bool wait_for_debugger;
+  bool is_installed;
+  EmbeddedWorkerSettings settings;
+};
+
+interface EmbeddedWorkerInstanceClient {
+  StartWorker(EmbeddedWorkerStartWorkerParams params);
+};