Fix PEM error checking

tests/standalone/io/security_context_argument_test.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import "package:expect/expect.dart";
 import "dart:io";
 
 String localFile(path) => Platform.script.resolve(path).toFilePath();
 
 bool printException(e) { print(e); return true; }
@@ skipping 17 matching lines @@
     Expect.throws(() => c.usePrivateKeySync(
         localFile('certificates/server_key_oops.pem'),
                   password: "dartdart"),
         fileSystemException);
     Expect.throws(() => c.usePrivateKeySync(1), argumentOrTypeError);
     Expect.throws(() => c.usePrivateKeySync(null), argumentError);
     Expect.throws(() => c.usePrivateKeySync(
         localFile('certificates/server_key.pem'), password: 3),
         argumentOrTypeError);
 
+    // Empty data.
+    Expect.throws(() => c.usePrivateKeyBytes([], password: 'dartdart'),
+        tlsException);
+    Expect.throws(() => c.setTrustedCertificatesBytes([]), tlsException);
+    Expect.throws(() => c.useCertificateChainBytes([]), tlsException);
+    Expect.throws(() => c.setClientAuthoritiesBytes([]), argumentError);
+
     // Malformed PEM certs.
     Expect.throws(() => c.usePrivateKeySync(
         localFile('certificates/client1_key_malformed.pem'),
         password: "dartdart"),
         tlsException);
     Expect.throws(() => c.setTrustedCertificatesSync(
         localFile('certificates/trusted_certs_malformed.pem')),
         tlsException);
     Expect.throws(() => c.useCertificateChainSync(
         localFile('certificates/server_chain_malformed1.pem')),
         tlsException);
     Expect.throws(() => c.useCertificateChainSync(
         localFile('certificates/server_chain_malformed2.pem')),
         tlsException);
     Expect.throws(() => c.setClientAuthoritiesSync(
         localFile('certificates/client_authority_malformed.pem')),
         argumentError);
 
     c.usePrivateKeySync(
         localFile('certificates/server_key.pem'), password: "dartdart");
 }
 
 void main() {
   testUsePrivateKeyArguments();
 }