Don't create unused OSError in Socket_Available.

runtime/bin/socket_patch.dart

Index: runtime/bin/socket_patch.dart
diff --git a/runtime/bin/socket_patch.dart b/runtime/bin/socket_patch.dart
index d598e273825b799e08ea8fed332508482b1d43c3..cd1cba9844af9e180ebb281968588ea1f076f381 100644
--- a/runtime/bin/socket_patch.dart
+++ b/runtime/bin/socket_patch.dart
@@ -572,7 +572,10 @@ class _NativeSocket extends _NativeSocketNativeWrapper with _ServiceObject {
       // the sum of all datagrams pending, so we need to call after each
       // receive. If available becomes > 0, the _NativeSocket will continue to
       // emit read events.
-      available = nativeAvailable();
+      var avail = nativeAvailable();
+      if (avail != null) {
+        available = avail;
+      }

[Ivan Posva, 2014/10/09 06:12:07]

available = (avail != null) avail : 1;

With the same comment about forcing the read from the socket as in the other
place nativeAvailable is called. Alternatively we could just have the native
code return a 1 instead of null. Removing the need for this adjustment.

[Anders Johnsen, 2014/10/09 06:17:07]

Done.

       totalRead += result.data.length;
     }
     readCount++;
@@ -745,7 +748,7 @@ class _NativeSocket extends _NativeSocketNativeWrapper with _ServiceObject {
             available++;
           } else {
             var avail = nativeAvailable();
-            if (avail is int) {
+            if (avail != null) {
               available = avail;
             } else {
               // Available failed. Mark socket as having data, to ensure read