Add webpack assets directly to xmodule fragments, rather than injecting them in fragment contents

common/templates/xblock_wrapper.html

-<%namespace name='static' file='static_content.html'/>
-
-% if is_xmodule:
-    <%static:webpack entry="${class_name}"/>
-% endif
-<!-- This is the xblock wrapper ${is_xmodule} -->
 <div class="${' '.join(classes) | n}" ${data_attributes}>
 % if js_init_parameters:
   <script type="json/xblock-args" class="xblock-json-init-args">

openedx/core/lib/xblock_utils/__init__.py

@@ -29,6 +29,8 @@ from xmodule.seq_module import SequenceModule
 from xmodule.vertical_block import VerticalBlock
 from xmodule.x_module import shim_xmodule_js, XModuleDescriptor, XModule, PREVIEW_VIEWS, STUDIO_VIEW
 
+import webpack_loader.utils
+
 log = logging.getLogger(__name__)
 
 
@@ -134,8 +136,6 @@ def wrap_xblock(
         'display_name': block.display_name_with_default_escaped,
         'data_attributes': u' '.join(u'data-{}="{}"'.format(markupsafe.escape(key), markupsafe.escape(value))
                                      for key, value in data.iteritems()),
-        'class_name': class_name,
-        'is_xmodule': isinstance(block, (XModule, XModuleDescriptor)),
     }
 
     if hasattr(frag, 'json_init_args') and frag.json_init_args is not None:
@@ -144,6 +144,11 @@ def wrap_xblock(
     else:
         template_context['js_init_parameters'] = ""
 
+    if isinstance(block, (XModule, XModuleDescriptor)):
+        # Add the webpackified asset tags
+        for tag in webpack_loader.utils.get_as_tags(class_name):
+            frag.add_resource(tag, mimetype='text/html', placement='head')
+
     return wrap_fragment(frag, render_to_string('xblock_wrapper.html', template_context))
 
 
@@ -202,7 +207,6 @@ def wrap_xblock_aside(
         'classes': css_classes,
         'data_attributes': u' '.join(u'data-{}="{}"'.format(markupsafe.escape(key), markupsafe.escape(value))
                                      for key, value in data.iteritems()),
-        'is_xmodule': False,
     }
 
     if hasattr(frag, 'json_init_args') and frag.json_init_args is not None: