Add support for raw HTML editor.

STUD-1562

common/lib/xmodule/xmodule/html_module.py

@@ -36,6 +36,16 @@ class HtmlFields(object):
         default=False,
         scope=Scope.settings
     )
+    editor = String(
+        help="Supports switching between the Visual Editor and the Raw HTML Editor. The change does not take effect until Save is pressed.",
+        display_name="Editor",
+        default="visual",
+        values=[
+            {"display_name": "Visual", "value": "visual"},
+            {"display_name": "Raw", "value": "raw"}
+        ],
+        scope=Scope.settings
+    )
 
 
 class HtmlModule(HtmlFields, XModule):
@@ -113,6 +123,7 @@ class HtmlDescriptor(HtmlFields, XmlDescriptor, EditingDescriptor):
         _context.update({
             'base_asset_url': StaticContent.get_base_url_path_for_course_assets(self.location) + '/',
             'enable_latex_compiler': self.use_latex_compiler,
+            'editor': self.editor
         })
         return _context