Add base 64 encoding to the crypto library utils.

tests/lib/crypto/base64_test.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.
+
+// Library tag to allow the test to run on Dartium.
+#library('base64_test');
+
+#import("dart:crypto");
+
+// Data from http://tools.ietf.org/html/rfc4648.
+var inputs =
+    const [ '', 'f', 'fo', 'foo', 'foob', 'fooba', 'foobar' ];
+var results =
+    const [ '', 'Zg==', 'Zm8=', 'Zm9v', 'Zm9vYg==', 'Zm9vYmE=', 'Zm9vYmFy' ];
+
+var longLine =
+    "Man is distinguished, not only by his reason, but by this singular "
+    "passion from other animals, which is a lust of the mind, that by a "
+    "perseverance of delight in the continued and indefatigable generation "
+    "of knowledge, exceeds the short vehemence of any carnal pleasure.";
+
+var longLineResult =
+    "TWFuIGlzIGRpc3Rpbmd1aXNoZWQsIG5vdCBvbm"
+    "x5IGJ5IGhpcyByZWFzb24sIGJ1dCBieSB0aGlz\r\n"
+    "IHNpbmd1bGFyIHBhc3Npb24gZnJvbSBvdGhlci"
+    "BhbmltYWxzLCB3aGljaCBpcyBhIGx1c3Qgb2Yg\r\n"
+    "dGhlIG1pbmQsIHRoYXQgYnkgYSBwZXJzZXZlcm"
+    "FuY2Ugb2YgZGVsaWdodCBpbiB0aGUgY29udGlu\r\n"
+    "dWVkIGFuZCBpbmRlZmF0aWdhYmxlIGdlbmVyYX"
+    "Rpb24gb2Yga25vd2xlZGdlLCBleGNlZWRzIHRo\r\n"
+    "ZSBzaG9ydCB2ZWhlbWVuY2Ugb2YgYW55IGNhcm"
+    "5hbCBwbGVhc3VyZS4=";
+
+var longLineResultNoBreak =
+    "TWFuIGlzIGRpc3Rpbmd1aXNoZWQsIG5vdCBvbm"
+    "x5IGJ5IGhpcyByZWFzb24sIGJ1dCBieSB0aGlz"
+    "IHNpbmd1bGFyIHBhc3Npb24gZnJvbSBvdGhlci"
+    "BhbmltYWxzLCB3aGljaCBpcyBhIGx1c3Qgb2Yg"
+    "dGhlIG1pbmQsIHRoYXQgYnkgYSBwZXJzZXZlcm"
+    "FuY2Ugb2YgZGVsaWdodCBpbiB0aGUgY29udGlu"
+    "dWVkIGFuZCBpbmRlZmF0aWdhYmxlIGdlbmVyYX"
+    "Rpb24gb2Yga25vd2xlZGdlLCBleGNlZWRzIHRo"
+    "ZSBzaG9ydCB2ZWhlbWVuY2Ugb2YgYW55IGNhcm"
+    "5hbCBwbGVhc3VyZS4=";
+
+void main() {
+  for (var i = 0; i < inputs.length; i++) {
+    var enc = CryptoUtils.bytesToBase64(inputs[i].charCodes());
+    Expect.equals(results[i], enc);
+  }
+  Expect.equals(CryptoUtils.bytesToBase64(longLine.charCodes(), 76),
+                longLineResult);
+  Expect.equals(CryptoUtils.bytesToBase64(longLine.charCodes()),
+                longLineResultNoBreak);
+}