Stop running pub get at gclient sync time and fix build bugs

mojo/public/dart/third_party/crypto/lib/src/crypto_utils.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.
+
+part of crypto;
+
+abstract class _CryptoUtils {
+  static String bytesToHex(List<int> bytes) {
+    var result = new StringBuffer();
+    for (var part in bytes) {
+      result.write('${part < 16 ? '0' : ''}${part.toRadixString(16)}');
+    }
+    return result.toString();
+  }
+
+  static String bytesToBase64(List<int> bytes,
+                              [bool urlSafe = false,
+                               bool addLineSeparator = false]) {
+    return BASE64.encode(bytes,
+                         urlSafe: urlSafe,
+                         addLineSeparator: addLineSeparator);
+  }
+
+  static List<int> base64StringToBytes(String input) {
+    return BASE64.decode(input);
+  }
+}