| Index: sdk/lib/io/base64.dart | 
| diff --git a/sdk/lib/io/base64.dart b/sdk/lib/io/base64.dart | 
| index f57eea6325562dfe3aef847b35cee8a18ee1f4a9..12c1e5f8367a87f96a782162093ebc91a84b1b3c 100644 | 
| --- a/sdk/lib/io/base64.dart | 
| +++ b/sdk/lib/io/base64.dart | 
| @@ -68,7 +68,7 @@ class _Base64 { | 
| int charCount = 0; | 
| int value = 0; | 
| for (int i = 0; i < data.length; i++) { | 
| -      int char = data.charCodeAt(i); | 
| +      int char = data.codeUnitAt(i); | 
| if (65 <= char && char <= 90) {  // "A" - "Z". | 
| value = (value << 6) | char - 65; | 
| charCount++; | 
|  |