Shows the error message while fetching the SW script in the DevTools console.

content/renderer/service_worker/embedded_worker_dispatcher.h

 // Copyright 2013 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.
 
 #ifndef CONTENT_RENDERER_SERVICE_WORKER_EMBEDDED_WORKER_DISPATCHER_H_
 #define CONTENT_RENDERER_SERVICE_WORKER_EMBEDDED_WORKER_DISPATCHER_H_
 
 #include <map>
 
 #include "base/id_map.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/time/time.h"
+#include "content/public/common/console_message_level.h"
 #include "ipc/ipc_listener.h"
 
 struct EmbeddedWorkerMsg_StartWorker_Params;
 class GURL;
 
 namespace content {
 
 // A tiny dispatcher which handles embedded worker start/stop messages.
 class EmbeddedWorkerDispatcher : public IPC::Listener {
  public:
   EmbeddedWorkerDispatcher();
   ~EmbeddedWorkerDispatcher() override;
 
   // IPC::Listener overrides.
   bool OnMessageReceived(const IPC::Message& message) override;
 
   void WorkerContextDestroyed(int embedded_worker_id);
 
  private:
   class WorkerWrapper;
 
   void OnStartWorker(const EmbeddedWorkerMsg_StartWorker_Params& params);
   void OnStopWorker(int embedded_worker_id);
   void OnResumeAfterDownload(int embedded_worker_id);
+  void OnAddMessageToConsole(int embedded_worker_id,
+                             ConsoleMessageLevel level,
+                             const std::string& message);
 
   IDMap<WorkerWrapper, IDMapOwnPointer> workers_;
   std::map<int /* embedded_worker_id */, base::TimeTicks> stop_worker_times_;
   base::WeakPtrFactory<EmbeddedWorkerDispatcher> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(EmbeddedWorkerDispatcher);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_SERVICE_WORKER_EMBEDDED_WORKER_DISPATCHER_H_