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

extensions/browser/api/socket/tcp_socket.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/socket/tcp_socket.h"
 
+#include "base/callback_helpers.h"
 #include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "extensions/browser/api/api_resource.h"
 #include "net/base/address_list.h"
 #include "net/base/ip_endpoint.h"
 #include "net/base/net_errors.h"
 #include "net/base/rand_callback.h"
 #include "net/socket/tcp_client_socket.h"
@@ skipping 91 matching lines @@
   if (result != net::ERR_IO_PENDING)
     OnConnectComplete(result);
 }
 
 void TCPSocket::Disconnect() {
   is_connected_ = false;
   if (socket_.get())
     socket_->Disconnect();
   server_socket_.reset(NULL);
   connect_callback_.Reset();
-  read_callback_.Reset();
+  // TODO(devlin): Should we do this for all callbacks?
+  if (!read_callback_.is_null()) {
+    base::ResetAndReturn(&read_callback_)
+        .Run(net::ERR_CONNECTION_CLOSED, nullptr);
+  }
   accept_callback_.Reset();
   accept_socket_.reset(NULL);
 }
 
 int TCPSocket::Bind(const std::string& address, uint16_t port) {
   return net::ERR_FAILED;
 }
 
 void TCPSocket::Read(int count, const ReadCompletionCallback& callback) {
   DCHECK(!callback.is_null());
@@ skipping 226 matching lines @@
 
 bool ResumableTCPSocket::IsPersistent() const { return persistent(); }
 
 ResumableTCPServerSocket::ResumableTCPServerSocket(
     const std::string& owner_extension_id)
     : TCPSocket(owner_extension_id), persistent_(false), paused_(false) {}
 
 bool ResumableTCPServerSocket::IsPersistent() const { return persistent(); }
 
 }  // namespace extensions