Removed SecurityContext.alpnSupported, as ALPN is now supported on all platforms. Also updated CHAN…

runtime/bin/security_context.cc

 // Copyright (c) 2017, 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.
 
 #if !defined(DART_IO_DISABLED) && !defined(DART_IO_SECURE_SOCKET_DISABLED)
 
 #include "bin/security_context.h"
 
 #include <openssl/bio.h>
 #include <openssl/err.h>
@@ skipping 791 matching lines @@
   ASSERT(context != NULL);
   ASSERT(password != NULL);
 
   int status = context->UseCertificateChainBytes(cert_chain_bytes, password);
 
   SecureSocketUtils::CheckStatus(status, "TlsException",
                                  "Failure in useCertificateChainBytes");
 }
 
 
-void FUNCTION_NAME(SecurityContext_AlpnSupported)(Dart_NativeArguments args) {
-  Dart_SetReturnValue(args, Dart_NewBoolean(true));
-}
-
-
 void FUNCTION_NAME(SecurityContext_TrustBuiltinRoots)(
     Dart_NativeArguments args) {
   SSLCertContext* context = SSLCertContext::GetSecurityContext(args);
 
   ASSERT(context != NULL);
 
   context->TrustBuiltinRoots();
 }
 
 
@@ skipping 30 matching lines @@
     Dart_ThrowException(DartUtils::NewDartArgumentError(
         "Non-boolean is_server argument passed to SetAlpnProtocols"));
   }
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // !defined(DART_IO_DISABLED) &&
         // !defined(DART_IO_SECURE_SOCKET_DISABLED)