[DevTools] Introduce DevToolsSession.

content/browser/devtools/browser_devtools_agent_host.cc

 // 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.
 
 #include "content/browser/devtools/browser_devtools_agent_host.h"
 
 #include "base/bind.h"
 #include "base/guid.h"
 #include "content/browser/devtools/devtools_protocol_handler.h"
+#include "content/browser/devtools/devtools_session.h"
 #include "content/browser/devtools/protocol/io_handler.h"
 #include "content/browser/devtools/protocol/memory_handler.h"
 #include "content/browser/devtools/protocol/system_info_handler.h"
 #include "content/browser/devtools/protocol/tethering_handler.h"
 #include "content/browser/devtools/protocol/tracing_handler.h"
 #include "content/browser/frame_host/frame_tree_node.h"
 
 namespace content {
 
 scoped_refptr<DevToolsAgentHost> DevToolsAgentHost::CreateForBrowser(
@@ skipping 53 matching lines @@
 
 bool BrowserDevToolsAgentHost::Close() {
   return false;
 }
 
 void BrowserDevToolsAgentHost::Reload() {
 }
 
 bool BrowserDevToolsAgentHost::DispatchProtocolMessage(
     const std::string& message) {
-  protocol_handler_->HandleMessage(session_id(), message);
+  protocol_handler_->HandleMessage(session() ? session()->session_id() : 0,
+                                   message);
   return true;
 }
 
 }  // content