MDL-43757 behat: Allowing the form field guesser to detect TinyMCE

It includes 2 more minor fixes:
- Escapes values sent to TinyMCE as it was breaking
  when values contained double quotes.
- Adding seconds to the screenshots directory to
  avoid using the same folder for multiple runs.

lib/behat/form_field/behat_form_editor.php

@@ -52,6 +52,7 @@ class behat_form_editor extends behat_form_field {
         if ($editorid = $this->get_editor_id()) {
 
             // Set the value to the iframe and save it to the textarea.
+            $value = str_replace('"', '\"', $value);
             $this->session->executeScript('
                 tinyMCE.get("'.$editorid.'").setContent("' . $value . '");
                 tinyMCE.get("'.$editorid.'").save();

lib/behat/form_field/behat_form_field.php

@@ -114,10 +114,22 @@ class behat_form_field {
         // Textareas are considered text based elements.
         $tagname = strtolower($this->field->getTagName());
         if ($tagname == 'textarea') {
-            return false;
-        }
 
-        if ($tagname == 'input') {
+            if (!$this->running_javascript()) {
+                return false;
+            }
+
+            // If there is an iframe with $id + _ifr there a TinyMCE editor loaded.
+            $xpath = '//iframe[@id="' . $this->field->getAttribute('id') . '_ifr"]';
+            if (!$this->session->getPage()->find('xpath', $xpath)) {
+
+                // Generic one if it is a normal textarea.
+                return false;
+            }
+
+            $classname = 'behat_form_editor';
+
+        } else if ($tagname == 'input') {
             $type = $this->field->getAttribute('type');
             switch ($type) {
                 case 'text':