[DevTools] Dedicated frontend for debugging Node.

chrome/browser/devtools/chrome_devtools_manager_delegate.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 "chrome/browser/devtools/chrome_devtools_manager_delegate.h"
 
 #include "base/memory/ptr_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "build/build_config.h"
 #include "chrome/browser/devtools/device/android_device_manager.h"
@@ skipping 226 matching lines @@
                    base::Unretained(this))));
   }
   remote_locations_.swap(remote_locations);
 }
 
 std::unique_ptr<base::DictionaryValue>
 ChromeDevToolsManagerDelegate::SetRemoteLocations(
     content::DevToolsAgentHost* agent_host,
     int command_id,
     base::DictionaryValue* params) {
-  if (host_data_.find(agent_host) == host_data_.end()) {
-      return DevToolsProtocol::CreateInvalidParamsResponse(
-          command_id, "Cannot find agent host");
-  }
+  // Could have been created late.
+  if (host_data_.find(agent_host) == host_data_.end())
+    DevToolsAgentHostAttached(agent_host);
 
   std::set<net::HostPortPair> tcp_locations;
   base::ListValue* locations;
   if (!params->GetList(kLocationsParam, &locations))
     return DevToolsProtocol::CreateInvalidParamsResponse(command_id,
                                                          kLocationsParam);
   for (const auto& item : *locations) {
     if (!item->IsType(base::Value::Type::DICTIONARY)) {
       return DevToolsProtocol::CreateInvalidParamsResponse(command_id,
                                                            kLocationsParam);
@@ skipping 13 matching lines @@
     tcp_locations.insert(net::HostPortPair(host, port));
   }
 
   host_data_[agent_host]->set_remote_locations(tcp_locations);
   UpdateDeviceDiscovery();
 
   std::unique_ptr<base::DictionaryValue> result(
       base::MakeUnique<base::DictionaryValue>());
   return DevToolsProtocol::CreateSuccessResponse(command_id, std::move(result));
 }