Remove _HttpUtils from dart:io.

sdk/lib/io/http_multipart_form_data_impl.dart

Index: sdk/lib/io/http_multipart_form_data_impl.dart
diff --git a/sdk/lib/io/http_multipart_form_data_impl.dart b/sdk/lib/io/http_multipart_form_data_impl.dart
index b2279541cc428a274aae780bac501a5354967c1a..8531a9522d7e4d5c838d2a35517e559303cab148 100644
--- a/sdk/lib/io/http_multipart_form_data_impl.dart
+++ b/sdk/lib/io/http_multipart_form_data_impl.dart
@@ -41,9 +41,9 @@ class _HttpMultipartFormData extends Stream implements HttpMultipartFormData {
           .transform(new StringDecoder(encoding))
           .expand((data) {
             buffer.write(data);
-            var out = _HttpUtils.decodeHttpEntityString(buffer.toString());
+            var out = _decodeHttpEntityString(buffer.toString());
             if (out != null) {
-              buffer = new StringBuffer();
+              buffer.clear();
               return [out];
             }
             return const [];
@@ -98,5 +98,42 @@ class _HttpMultipartFormData extends Stream implements HttpMultipartFormData {
   String value(String name) {
     return _mimeMultipart.headers[name];
   }
+
+  // Decode a string with HTTP entities. Returns null if the string ends in the
+  // middle of a http entity.
+  static String _decodeHttpEntityString(String input) {
+    int amp = input.lastIndexOf('&');
+    if (amp < 0) return input;
+    int end = input.lastIndexOf(';');
+    if (end < amp) return null;
+
+    var buffer = new StringBuffer();
+    int offset = 0;
+
+    parse(amp, end) {
+      switch (input[amp + 1]) {
+        case '#':
+          if (input[amp + 2] == 'x') {
+            buffer.writeCharCode(
+                int.parse(input.substring(amp + 3, end), radix: 16));
+          } else {
+            buffer.writeCharCode(int.parse(input.substring(amp + 2, end)));
+          }
+          break;
+
+        default:
+          throw new HttpException('Unhandled HTTP entity token');
+      }
+    }
+
+    while ((amp = input.indexOf('&', offset)) >= 0) {
+      buffer.write(input.substring(offset, amp));
+      int end = input.indexOf(';', amp);
+      parse(amp, end);
+      offset = end + 1;
+    }
+    buffer.write(input.substring(offset));
+    return buffer.toString();
+  }
 }