Extend dart:io error handling to all socket functions

runtime/bin/eventhandler_linux.cc

Index: runtime/bin/eventhandler_linux.cc
diff --git a/runtime/bin/eventhandler_linux.cc b/runtime/bin/eventhandler_linux.cc
index 5ee2f84d69f020933430ee334064bd7797c02c21..2609dc5d76aff52dbb77c97dc57263ff4e48f6ac 100644
--- a/runtime/bin/eventhandler_linux.cc
+++ b/runtime/bin/eventhandler_linux.cc
@@ -261,8 +261,14 @@ intptr_t EventHandlerImplementation::GetPollEvents(intptr_t events,
     if ((events & EPOLLIN) != 0) {
       if (FDUtils::AvailableBytes(sd->fd()) != 0) {
         event_mask = (1 << kInEvent);
-      } else if (((events & EPOLLHUP) != 0)) {
-        event_mask = (1 << kCloseEvent);
+      } else if ((events & EPOLLHUP) != 0) {
+        // If both EPOLLHUP and EPOLLERR are reported treat it as an
+        // error.
+        if ((events & EPOLLERR) != 0) {
+          event_mask = (1 << kErrorEvent);
+        } else {
+          event_mask = (1 << kCloseEvent);
+        }
         sd->MarkClosedRead();
       } else if ((events & EPOLLERR) != 0) {
         event_mask = (1 << kErrorEvent);