[Extensions] DCHECK that ExtensionFunctions respond (and only once)

extensions/browser/api/bluetooth_socket/bluetooth_socket_api.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 "extensions/browser/api/bluetooth_socket/bluetooth_socket_api.h"
 
 #include <stdint.h>
 #include <utility>
 
 #include "content/public/browser/browser_context.h"
@@ skipping 186 matching lines @@
 
   bluetooth_socket::SocketProperties* properties =
       params_.get()->properties.get();
   if (properties) {
     SetSocketProperties(socket, properties);
   }
 
   bluetooth_socket::CreateInfo create_info;
   create_info.socket_id = AddSocket(socket);
   results_ = bluetooth_socket::Create::Results::Create(create_info);
-  AsyncWorkCompleted();
+  // AsyncWorkCompleted is called by AsyncWorkStart().
 }
 
 BluetoothSocketUpdateFunction::BluetoothSocketUpdateFunction() {}
 
 BluetoothSocketUpdateFunction::~BluetoothSocketUpdateFunction() {}
 
 bool BluetoothSocketUpdateFunction::Prepare() {
   params_ = bluetooth_socket::Update::Params::Create(*args_);
   EXTENSION_FUNCTION_VALIDATE(params_.get());
   return true;
@@ skipping 445 matching lines @@
       if (socket) {
         socket_infos.push_back(CreateSocketInfo(socket_id, socket));
       }
     }
   }
   results_ = bluetooth_socket::GetSockets::Results::Create(socket_infos);
 }
 
 }  // namespace api
 }  // namespace extensions