Cleanup: Remove unneeded forward declarations in webkit/.

webkit/tools/test_shell/test_shell_devtools_agent.h

 // Copyright (c) 2011 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 TEST_SHELL_DEVTOOLS_AGENT_H_
-#define TEST_SHELL_DEVTOOLS_AGENT_H_
+#ifndef WEBKIT_TOOLS_TEST_SHELL_TEST_SHELL_DEVTOOLS_AGENT_H_
+#define WEBKIT_TOOLS_TEST_SHELL_TEST_SHELL_DEVTOOLS_AGENT_H_
+
+#include <string>
 
 #include "base/memory/weak_ptr.h"
 #include "base/task.h"
 
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebDevToolsAgentClient.h"
 
 namespace WebKit {
 
 class WebDevToolsAgent;
 class WebView;
-struct WebDevToolsMessageData;
 
-} // namespace WebKit
+}  // namespace WebKit
 
 class TestShellDevToolsCallArgs;
 class TestShellDevToolsClient;
 
 class TestShellDevToolsAgent : public WebKit::WebDevToolsAgentClient {
  public:
   TestShellDevToolsAgent();
   virtual ~TestShellDevToolsAgent();
 
   void SetWebView(WebKit::WebView* web_view);
@@ skipping 24 matching lines @@
 
   base::WeakPtrFactory<TestShellDevToolsAgent> weak_factory_;
   TestShellDevToolsClient* dev_tools_client_;
   int routing_id_;
   WebKit::WebDevToolsAgent* web_dev_tools_agent_;
   WebKit::WebView* web_view_;
 
   DISALLOW_COPY_AND_ASSIGN(TestShellDevToolsAgent);
 };
 
-#endif  // TEST_SHELL_DEVTOOLS_AGENT_H_
+#endif  // WEBKIT_TOOLS_TEST_SHELL_TEST_SHELL_DEVTOOLS_AGENT_H_