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

extensions/browser/api/socket/tcp_socket.cc

Index: extensions/browser/api/socket/tcp_socket.cc
diff --git a/extensions/browser/api/socket/tcp_socket.cc b/extensions/browser/api/socket/tcp_socket.cc
index 5053b869378fc05aaddaf1a27cf75ed0d60d539b..f3ba5ee48d26621eb9822aa0356635f5cf368a52 100644
--- a/extensions/browser/api/socket/tcp_socket.cc
+++ b/extensions/browser/api/socket/tcp_socket.cc
@@ -4,6 +4,7 @@
 
 #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"
@@ -115,7 +116,11 @@ void TCPSocket::Disconnect() {
     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);
 }