[DevTools] Support multiple sessions in Target domain

content/browser/devtools/devtools_agent_host_impl.h

 // Copyright (c) 2012 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_DEVTOOLS_AGENT_HOST_IMPL_H_
 #define CONTENT_BROWSER_DEVTOOLS_DEVTOOLS_AGENT_HOST_IMPL_H_
 
 #include <stdint.h>
 
 #include <string>
@@ skipping 26 matching lines @@
   std::string GetParentId() override;
   std::string GetDescription() override;
   GURL GetFaviconURL() override;
   std::string GetFrontendURL() override;
   base::TimeTicks GetLastActivityTime() override;
   BrowserContext* GetBrowserContext() override;
   WebContents* GetWebContents() override;
   void DisconnectWebContents() override;
   void ConnectWebContents(WebContents* wc) override;
 
+  void AttachMultiClient(DevToolsAgentHostClient* client);
   bool Inspect();
 
  protected:
   DevToolsAgentHostImpl(const std::string& id);
   ~DevToolsAgentHostImpl() override;
 
   static bool ShouldForceCreation();
 
   virtual void AttachSession(DevToolsSession* session) = 0;
   virtual void DetachSession(int session_id) = 0;
@@ skipping 46 matching lines @@
   SendMessageCallback callback_;
   std::string message_buffer_;
   uint32_t message_buffer_size_;
   std::string state_cookie_;
   int last_call_id_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_DEVTOOLS_DEVTOOLS_AGENT_HOST_IMPL_H_