[DevTools] Filter any messages from previous sessions in DevToolsAgentHostImpl

content/browser/devtools/protocol/devtools_protocol_delegate.h

+// Copyright 2015 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_PROTOCOL_DEVTOOLS_PROTOCOL_DELEGATE_H_
+#define CONTENT_BROWSER_DEVTOOLS_PROTOCOL_DEVTOOLS_PROTOCOL_DELEGATE_H_
+
+#include "content/common/content_export.h"
+
+namespace content {
+
+class CONTENT_EXPORT DevToolsProtocolDelegate {
+public:
+  virtual ~DevToolsProtocolDelegate(){}
+  virtual void SendProtocolResponse(int session_id,
+                                    const std::string& message) = 0;
+  virtual void SendProtocolNotification(const std::string& message) = 0;
+};
+
+} // content
+
+#endif // CONTENT_BROWSER_DEVTOOLS_PROTOCOL_DEVTOOLS_PROTOCOL_DELEGATE_H_