Reapply change to hide VM-only List implementation classes.

runtime/bin/socket_impl.dart

 // Copyright (c) 2012, 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.
 
 
 class _SocketBase extends NativeFieldWrapperClass1 {
   // Bit flags used when communicating between the eventhandler and
   // dart code. The EVENT flags are used to indicate events of
   // interest when sending a message from dart code to the
   // eventhandler. When receiving a message from the eventhandler the
@@ skipping 386 matching lines @@
       }
       if (offset < 0) {
         throw new IndexOutOfRangeException(offset);
       }
       if (bytes < 0) {
         throw new IndexOutOfRangeException(bytes);
       }
       if ((offset + bytes) > buffer.length) {
         throw new IndexOutOfRangeException(offset + bytes);
       }
-      // When using the Dart C API to access raw data, using a ByteArray is
-      // currently much faster. This function will make a copy of the
-      // supplied List to a ByteArray if it isn't already.
-      List outBuffer;
-      int outOffset = offset;
-      if (buffer is Uint8List || buffer is ObjectArray) {
-        outBuffer = buffer;
-      } else {
-        outBuffer = new Uint8List(bytes);
-        outOffset = 0;
-        int j = offset;
-        for (int i = 0; i < bytes; i++) {
-          int value = buffer[j];
-          if (value is! int) {
-            throw new FileIOException(
-                "List element is not an integer at index $j");
-          }
-          outBuffer[i] = value;
-          j++;
-        }
-      }
-      var result = _writeList(outBuffer, outOffset, bytes);
+      var fastBuffer = _ensureFastAndSerializableBuffer(buffer, offset, bytes);
+      var result = _writeList(fastBuffer[0], fastBuffer[1], bytes);
       if (result is OSError) {
         _reportError(result, "Write failed");
         // If writing fails we return 0 as the number of bytes and
         // report the error on the error handler.
         result = 0;
       }
       return result;
     }
     throw new SocketIOException("writeList failed - invalid socket handle");
   }
@@ skipping 148 matching lines @@
   bool _seenFirstOutEvent = false;
   bool _pipe = false;
   Function _clientConnectHandler;
   Function _clientWriteHandler;
   SocketInputStream _inputStream;
   SocketOutputStream _outputStream;
   String _remoteHost;
   int _remotePort;
   static SendPort _socketService;
 }