Fix Unicode issues in dart2js and dart2dart.

sdk/lib/io/string_stream.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.
 
 // Interface for decoders decoding binary data into string data. The
 // decoder keeps track of line breaks during decoding.
 abstract class _StringDecoder {
   // Add more binary data to be decoded. The ownership of the buffer
   // is transfered to the decoder and the caller most not modify it any more.
   int write(List<int> buffer);
@@ skipping 250 matching lines @@
   List<int> encodeString(String string) {
     int size = _encodingSize(string);
     List<int> result = new Uint8List(size);
     _encodeString(string, result);
     return result;
   }
 
   static int _encodingSize(String string) => _encodeString(string, null);
 
   static int _encodeString(String string, List<int> buffer) {
-    int pos = 0;
-    int length = string.length;
-    for (int i = 0; i < length; i++) {
-      int additionalBytes;
-      int charCode = string.charCodeAt(i);
-      if (charCode <= 0x007F) {
-        additionalBytes = 0;
-        if (buffer != null) buffer[pos] = charCode;
-      } else if (charCode <= 0x07FF) {
-        // 110xxxxx (xxxxx is top 5 bits).
-        if (buffer != null) buffer[pos] = ((charCode >> 6) & 0x1F) | 0xC0;
-        additionalBytes = 1;
-      } else if (charCode <= 0xFFFF) {
-        // 1110xxxx (xxxx is top 4 bits)
-        if (buffer != null) buffer[pos] = ((charCode >> 12) & 0x0F)| 0xE0;
-        additionalBytes = 2;
-      } else {
-        // 11110xxx (xxx is top 3 bits)
-        if (buffer != null) buffer[pos] = ((charCode >> 18) & 0x07) | 0xF0;
-        additionalBytes = 3;
-      }
-      pos++;
-      if (buffer != null) {
-        for (int i = additionalBytes; i > 0; i--) {
-          // 10xxxxxx (xxxxxx is next 6 bits from the top).
-          buffer[pos++] = ((charCode >> (6 * (i - 1))) & 0x3F) | 0x80;
-        }
-      } else {
-        pos += additionalBytes;
+    List<int> utf8CodeUnits = encodeUtf8(string);
+    if (buffer != null) {
+      for (int i = 0; i < utf8CodeUnits.length; i++) {
+        buffer[i] = utf8CodeUnits[i];
       }
     }
-    return pos;
+    return utf8CodeUnits.length;
   }
 }
 
 
 // Utility class for encoding a string into a Latin1 byte stream.
 class _Latin1Encoder implements _StringEncoder {
   List<int> encodeString(String string) {
     List<int> result = new Uint8List(string.length);
     for (int i = 0; i < string.length; i++) {
       int charCode = string.charCodeAt(i);
@@ skipping 220 matching lines @@
   bool _inputClosed = false;  // Is the underlying input stream closed?
   bool _closed = false;  // Is this stream closed.
   bool _eof = false;  // Has all data been read from the decoder?
   Timer _scheduledDataCallback;
   Timer _scheduledLineCallback;
   Timer _scheduledCloseCallback;
   Function _clientDataHandler;
   Function _clientLineHandler;
   Function _clientCloseHandler;
 }