MAGETWO-57816: [Backport] - [GitHub] UTF-8 special character issue in widgets #4232 - for 2.0

Author: OlgaVasyltsun

lib/web/legacy-build.min.js

@@ -332,12 +332,12 @@ var Base64 = {
         var chr1, chr2, chr3, enc1, enc2, enc3, enc4;
         var i = 0;
 
+        input = Base64._utf8_encode(input);
+
         if( typeof window.btoa === "function" ){
             return window.btoa(input);
         }
 
-        input = Base64._utf8_encode(input);
-
         while (i < input.length) {
 
             chr1 = input.charCodeAt(i++);
@@ -370,7 +370,7 @@ var Base64 = {
         var i = 0;
 
         if( typeof window.atob === "function" ){
-            return window.atob(input);
+            return Base64._utf8_decode(window.atob(input));
         }
 
         input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");
@@ -395,8 +395,8 @@ var Base64 = {
                 output = output + String.fromCharCode(chr3);
             }
         }
-        output = Base64._utf8_decode(output);
-        return output;
+
+        return Base64._utf8_decode(output);
     },
 
     mageEncode: function(input){