Move the snippet chooser HTML markup from snippet_chooser_panel.html entirely within the AdminSnippetChooser widget's render() method

wagtail/wagtailsnippets/edit_handlers.py

@@ -10,7 +10,6 @@ from .widgets import AdminSnippetChooser
 
 
 class BaseSnippetChooserPanel(BaseChooserPanel):
-    field_template = "wagtailsnippets/edit_handlers/snippet_chooser_panel.html"
     object_type_name = 'item'
 
     _content_type = None

wagtail/wagtailsnippets/templates/wagtailsnippets/edit_handlers/snippet_chooser_panel.html

@@ -1,8 +1,2 @@
-{% extends "wagtailadmin/edit_handlers/chooser_panel.html" %}
-{% load i18n %}
-
-{% block chooser_class %}snippet-chooser{% endblock %}
-
-{% block chosen_state_view %}
-    <span class="title">{{ item }}</span>
-{% endblock %}
+{# Snippet chooser is now implemented as an entirely standard form widget - snippet_chooser_panel.html is redundant #}
+{% include "wagtailadmin/shared/field.html" %}

wagtail/wagtailsnippets/templates/wagtailsnippets/widgets/snippet_chooser.html

@@ -0,0 +1,7 @@
+{% extends "wagtailadmin/widgets/chooser.html" %}
+
+{% block chooser_class %}snippet-chooser{% endblock %}
+
+{% block chosen_state_view %}
+    <span class="title">{{ item }}</span>
+{% endblock %}

wagtail/wagtailsnippets/widgets.py

@@ -2,6 +2,7 @@ from __future__ import absolute_import, unicode_literals
 
 import json
 
+from django.template.loader import render_to_string
 from django.utils.translation import ugettext_lazy as _
 
 from wagtail.wagtailadmin.widgets import AdminChooser
@@ -20,6 +21,20 @@ class AdminSnippetChooser(AdminChooser):
         if content_type is not None:
             self.target_content_type = content_type
 
+    def render_html(self, name, value, attrs):
+        original_field_html = super(AdminSnippetChooser, self).render_html(name, value, attrs)
+
+        model_class = self.target_content_type.model_class()
+        instance = self.get_instance(model_class, value)
+
+        return render_to_string("wagtailsnippets/widgets/snippet_chooser.html", {
+            'widget': self,
+            'original_field_html': original_field_html,
+            'attrs': attrs,
+            'value': value,
+            'item': instance,
+        })
+
     def render_js_init(self, id_, name, value):
         content_type = self.target_content_type