Created CustomTagTemplateBlock to use with CustomTagBlock instead of RawDescriptor.

common/lib/xmodule/setup.py

@@ -9,7 +9,6 @@ XMODULES = [
     "section = xmodule.backcompat_module:SemanticSectionDescriptor",
     "slides = xmodule.backcompat_module:TranslateCustomTagDescriptor",
     "videodev = xmodule.backcompat_module:TranslateCustomTagDescriptor",
-    "custom_tag_template = xmodule.raw_module:RawDescriptor",
     "raw = xmodule.raw_module:RawDescriptor",
 ]
 XBLOCKS = [
@@ -20,6 +19,7 @@ XBLOCKS = [
     "course = xmodule.course_module:CourseBlock",
     "course_info = xmodule.html_module:CourseInfoBlock",
     "customtag = xmodule.template_module:CustomTagBlock",
+    "custom_tag_template = xmodule.template_module:CustomTagTemplateBlock",
     "error = xmodule.error_module:ErrorBlock",
     "hidden = xmodule.hidden_module:HiddenDescriptor",
     "html = xmodule.html_module:HtmlBlock",

common/lib/xmodule/xmodule/template_module.py

@@ -21,7 +21,7 @@ from xmodule.x_module import (
 from xmodule.xml_module import XmlMixin
 
 
-class CustomTagBlock(
+class CustomTagTemplateBlock(  # pylint: disable=abstract-method
     RawMixin,
     XmlMixin,
     EditingMixin,
@@ -30,7 +30,15 @@ class CustomTagBlock(
     HTMLSnippet,
     ResourceTemplates,
     XModuleMixin,
-):  # pylint: disable=abstract-method
+):
+    """
+    A block which provides templates for CustomTagBlock. The template name
+    is set on the `impl` attribute of CustomTagBlock. See below for more details
+    on how to use it.
+    """
+
+
+class CustomTagBlock(CustomTagTemplateBlock):  # pylint: disable=abstract-method
     """
     This module supports tags of the form
     <customtag option="val" option2="val2" impl="tagname"/>