content: Cleanup class/struct forward declarations

content/browser/devtools/worker_devtools_agent_host.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_BROWSER_DEVTOOLS_WORKER_DEVTOOLS_AGENT_HOST_H_
 #define CONTENT_BROWSER_DEVTOOLS_WORKER_DEVTOOLS_AGENT_HOST_H_
 
 #include "base/macros.h"
 #include "content/browser/devtools/devtools_agent_host_impl.h"
 #include "ipc/ipc_listener.h"
 
 namespace content {
 
 namespace devtools { namespace schema { class SchemaHandler; }}
 
 class BrowserContext;
 class DevToolsProtocolHandler;
-class SharedWorkerInstance;
 
 class WorkerDevToolsAgentHost : public DevToolsAgentHostImpl,
                                 public IPC::Listener {
  public:
   typedef std::pair<int, int> WorkerId;
 
   // DevToolsAgentHost override.
   BrowserContext* GetBrowserContext() override;
   bool DispatchProtocolMessage(const std::string& message) override;
 
@@ skipping 42 matching lines @@
   std::unique_ptr<DevToolsProtocolHandler> protocol_handler_;
   DevToolsMessageChunkProcessor chunk_processor_;
   WorkerState state_;
   WorkerId worker_id_;
   DISALLOW_COPY_AND_ASSIGN(WorkerDevToolsAgentHost);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_DEVTOOLS_WORKER_DEVTOOLS_AGENT_HOST_H_