Eliminate template tags from embed chooser JS

wagtail/embeds/templates/wagtailembeds/chooser/embed_chosen.js

@@ -1,4 +1,4 @@
-function(modal) {
-    modal.respond('embedChosen', '{{ embed_html|escapejs }}', {{ embed_json|safe }});
+function(modal, jsonData) {
+    modal.respond('embedChosen', jsonData['embed_html'], jsonData['embed_data']);
     modal.close();
-}
+}

wagtail/embeds/views/chooser.py

@@ -1,5 +1,3 @@
-import json
-
 from django.forms.utils import ErrorList
 from django.utils.translation import ugettext as _
 
@@ -28,17 +26,17 @@ def chooser_upload(request):
             try:
                 embed_html = embed_to_editor_html(form.cleaned_data['url'])
                 embed_obj = embeds.get_embed(form.cleaned_data['url'])
-                embed_json = json.dumps({
+                embed_data = {
                     'embedType': embed_obj.type,
                     'url': embed_obj.url,
                     'providerName': embed_obj.provider_name,
                     'authorName': embed_obj.author_name,
                     'thumbnail': embed_obj.thumbnail_url,
                     'title': embed_obj.title,
-                })
+                }
                 return render_modal_workflow(
                     request, None, 'wagtailembeds/chooser/embed_chosen.js',
-                    {'embed_html': embed_html, 'embed_json': embed_json}
+                    None, json_data={'embed_html': embed_html, 'embed_data': embed_data}
                 )
             except AccessDeniedEmbedlyException:
                 error = _("There seems to be a problem with your embedly API key. Please check your settings.")