only execude code when backbone is defined

lms/static/coffee/src/discussion/content.coffee

-class @Content extends Backbone.Model
+if Backbone?
+  class @Content extends Backbone.Model
 
     template: -> DiscussionUtil.getTemplate('_content')
 
@@ -49,7 +50,7 @@ class @Content extends Backbone.Model
       @resetComments(@get('children'))
       
 
-class @ContentView extends Backbone.View
+  class @ContentView extends Backbone.View
 
     $: (selector) ->
       @$local.find(selector)
@@ -352,7 +353,7 @@ class @ContentView extends Backbone.View
       @initBody()
       @initCommentViews()
       
-class @Thread extends @Content
+  class @Thread extends @Content
     urlMappers:
       'retrieve' : -> DiscussionUtil.urlFor('retrieve_single_thread', @discussion.id, @id)
       'reply'    : -> DiscussionUtil.urlFor('create_comment', @id)
@@ -373,9 +374,9 @@ class @Thread extends @Content
       discussion_id = @get('commentable_id')
       return Discussion.urlFor("permanent_link_thread", discussion_id, @id)
 
-class @ThreadView extends @ContentView
+  class @ThreadView extends @ContentView
 
-class @Comment extends @Content
+  class @Comment extends @Content
     urlMappers:
       'reply': -> DiscussionUtil.urlFor('create_sub_comment', @id)
       'unvote': -> DiscussionUtil.urlFor("undo_vote_for_#{@get('type')}", @id)
@@ -396,9 +397,9 @@ class @Comment extends @Content
         count += comment.getCommentsCount() + 1
       count
 
-class @CommentView extends @ContentView
+  class @CommentView extends @ContentView
 
-class @Comments extends Backbone.Collection
+  class @Comments extends Backbone.Collection
 
     model: Comment
 

lms/static/coffee/src/discussion/discussion.coffee

-class @Discussion extends Backbone.Collection
+if Backbone?
+  class @Discussion extends Backbone.Collection
     model: Thread
 
     initialize: ->
@@ -15,7 +16,7 @@ class @Discussion extends Backbone.Collection
       @add model
       model
 
-class @DiscussionView extends Backbone.View
+  class @DiscussionView extends Backbone.View
 
     $: (selector) ->
       @$local.find(selector)

lms/static/coffee/src/discussion/discussion_module.coffee

-class @DiscussionModuleView extends Backbone.View
+if Backbone?
+  class @DiscussionModuleView extends Backbone.View
     events:
       "click .discussion-show": "toggleDiscussion"
     toggleDiscussion: (event) ->

lms/static/coffee/src/discussion/main.coffee

@@ -12,4 +12,5 @@ $ ->
     discussion.reset(discussionData, {silent: false})
     view = new DiscussionView(el: elem, model: discussion)
 
+  if window.$$annotated_content_info?
     DiscussionUtil.bulkUpdateContentInfo(window.$$annotated_content_info)