MAGETWO-45436: Eliminate multiple escaping in the inline translation popup

 - decoded all special characters before displaying in translation dialog
 - remove additional encoding from dialog's Custom field

Author: Cari Spruiell

app/code/Magento/Translation/Model/Inline/Parser.php

@@ -365,10 +365,10 @@ private function _getTranslateData($regexp, &$text, $locationCallback, $options
         while (preg_match($regexp, $text, $matches, PREG_OFFSET_CAPTURE, $next)) {
             $trArr[] = json_encode(
                 [
-                    'shown' => htmlspecialchars($matches[1][0]),
-                    'translated' => htmlspecialchars($matches[2][0]),
-                    'original' => $matches[3][0],
-                    'location' => htmlspecialchars(call_user_func($locationCallback, $matches, $options)),
+                    'shown' => htmlspecialchars_decode($matches[1][0]),
+                    'translated' => htmlspecialchars_decode($matches[2][0]),
+                    'original' => htmlspecialchars_decode($matches[3][0]),
+                    'location' => htmlspecialchars_decode(call_user_func($locationCallback, $matches, $options)),
                 ]
             );
             $text = substr_replace($text, $matches[1][0], $matches[0][1], strlen($matches[0][0]));

app/code/Magento/Translation/Model/ResourceModel/StringUtils.php

@@ -209,7 +209,6 @@ public function deleteTranslate($string, $locale = null, $storeId = null)
     public function saveTranslate($string, $translate, $locale = null, $storeId = null)
     {
         $string = htmlspecialchars_decode($string);
-        $translate = htmlspecialchars_decode($translate);
         $connection = $this->getConnection();
         $table = $this->getMainTable();
         $translate = htmlspecialchars($translate, ENT_QUOTES);

app/code/Magento/Translation/view/adminhtml/templates/translate_inline.phtml

@@ -42,7 +42,7 @@
                         <input id="custom_<%- i %>"
                                name="translate[<%- i %>][custom]"
                                class="input-text"
-                               value="<%- data.escape(item.translated) %>" />
+                               value="<%- item.translated %>" />
                     </td>
                 </tr>
             </table></div>

app/code/Magento/Translation/view/frontend/templates/translate_inline.phtml

@@ -39,11 +39,11 @@
                             <label for="custom_<%- i %>">Custom:</label>
                         </th>
                         <td class="value">
-                            <input name="translate[<%- i %>][original]" type="hidden" value="<%- data.escape(item.original) %>"/>
+                            <input name="translate[<%- i %>][original]" type="hidden" value="<%- item.original %>"/>
                             <input id="custom_<%- i %>"
                                    name="translate[<%- i %>][custom]"
                                    class="input-text"
-                                   value="<%- data.escape(item.translated) %>" />
+                                   value="<%- item.translated %>" />
                         </td>
                     </tr>
                 </table>