Remove deprecated StringBuffer.add, addAll and addCharCode.

runtime/lib/integers.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.
 
 // TODO(srdjan): fix limitations.
 // - shift amount must be a Smi.
 class _IntegerImplementation {
   factory _IntegerImplementation._uninstantiable() {
     throw new UnsupportedError(
         "_IntegerImplementation can only be allocated by the VM");
@@ skipping 179 matching lines @@
     List temp = new List();
     while (value > 0) {
       int digit = value % radix;
       value ~/= radix;
       temp.add(digit);
     }
     if (temp.isEmpty) {
       return "0";
     }
     StringBuffer buffer = new StringBuffer();
-    if (isNegative) buffer.add("-");
+    if (isNegative) buffer.write("-");
     for (int i = temp.length - 1; i >= 0; i--) {
-      buffer.add(table[temp[i]]);
+      buffer.write(table[temp[i]]);
     }
     return buffer.toString();
   }
 }
 
 class _Smi extends _IntegerImplementation implements int {
   factory _Smi._uninstantiable() {
     throw new UnsupportedError(
         "_Smi can only be allocated by the VM");
   }
@@ skipping 50 matching lines @@
     }
   }
   int _shlFromInt(int other) {
     throw const OutOfMemoryError();
   }
 
   int pow(int exponent) {
     throw "Bigint.pow not implemented";
   }
 }