DevTools: expose session to handlers.

content/browser/devtools/protocol/devtools_domain_handler.h

 // Copyright 2016 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_DOMAIN_HANDLER_H_
 #define CONTENT_BROWSER_DEVTOOLS_PROTOCOL_DEVTOOLS_DOMAIN_HANDLER_H_
 
 #include "content/browser/devtools/protocol/forward.h"
 
 namespace content {
 
+class DevToolsSession;
+class DevToolsAgentHostImpl;
 class RenderFrameHostImpl;
 
 namespace protocol {
 
 class DevToolsDomainHandler {
  public:
   explicit DevToolsDomainHandler(const std::string& name);
   virtual ~DevToolsDomainHandler();
 
   virtual void SetRenderFrameHost(RenderFrameHostImpl* host);
   virtual void Wire(UberDispatcher* dispatcher);
   virtual Response Disable();
 
   const std::string& name() const { return name_; }
 
+ protected:
+  static DevToolsSession* GetFirstSession(DevToolsAgentHostImpl* host);
+
  private:
   std::string name_;
 
   DISALLOW_COPY_AND_ASSIGN(DevToolsDomainHandler);
 };
 
 }  // namespace protocol
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_DEVTOOLS_PROTOCOL_DEVTOOLS_DOMAIN_HANDLER_H_