content: Cleanup class/struct forward declarations

content/renderer/service_worker/embedded_worker_devtools_agent.h

 // 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.
 
 #ifndef CONTENT_RENDERER_SERVICE_WORKER_EMBEDDED_WORKER_DEVTOOLS_AGENT_H_
 #define CONTENT_RENDERER_SERVICE_WORKER_EMBEDDED_WORKER_DEVTOOLS_AGENT_H_
 
 #include <string>
 
 #include "base/macros.h"
 #include "ipc/ipc_listener.h"
 
 namespace IPC {
 class Message;
 }
 
 namespace blink {
 class WebEmbeddedWorker;
-class WebString;
 }
 
 namespace content {
 
 class EmbeddedWorkerDevToolsAgent : public IPC::Listener {
  public:
   EmbeddedWorkerDevToolsAgent(blink::WebEmbeddedWorker* webworker,
                               int route_id);
   ~EmbeddedWorkerDevToolsAgent() override;
 
@@ skipping 12 matching lines @@
 
   blink::WebEmbeddedWorker* webworker_;
   int route_id_;
 
   DISALLOW_COPY_AND_ASSIGN(EmbeddedWorkerDevToolsAgent);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_SERVICE_WORKER_EMBEDDED_WORKER_DEVTOOLS_AGENT_H_