Implements secure sockets on Mac OS with SecureTransport API

sdk/lib/io/secure_socket.dart

Index: sdk/lib/io/secure_socket.dart
diff --git a/sdk/lib/io/secure_socket.dart b/sdk/lib/io/secure_socket.dart
index cf8dec0eb80aa287d07e544611304a26d36b0c80..c271d77794f12673e56372aed54a7ba0279b3739 100644
--- a/sdk/lib/io/secure_socket.dart
+++ b/sdk/lib/io/secure_socket.dart
@@ -970,8 +970,16 @@ class _RawSecureSocket extends Stream<RawSocketEvent>
 
     return _IOService._dispatch(_SSL_PROCESS_FILTER, args).then((response) {
       if (response.length == 2) {
-        _reportError(new TlsException('${response[1]} error ${response[0]}'),
-                     null);
+        if (wasInHandshake) {
+          // If we're in handshake, throw a handshake error.
+          _reportError(
+              new HandshakeException('${response[1]} error ${response[0]}'),
+              null);
+        } else {
+          // If we're connected, throw a TLS error.
+          _reportError(new TlsException('${response[1]} error ${response[0]}'),
+                       null);
+        }
       }
       int start(int index) => response[2 * index];
       int end(int index) => response[2 * index + 1];