diff --git a/actionpack/lib/abstract_controller/rendering.rb b/actionpack/lib/abstract_controller/rendering.rb
index 2bb7c2139e0bd..6db0941b52560 100644
--- a/actionpack/lib/abstract_controller/rendering.rb
+++ b/actionpack/lib/abstract_controller/rendering.rb
@@ -23,8 +23,8 @@ module Rendering
     def render(*args, &block)
       options = _normalize_render(*args, &block)
       self.response_body = render_to_body(options)
-      if options[:plain]
-        _set_content_type Mime::TEXT.to_s
+      if options[:html]
+        _set_content_type Mime::HTML.to_s
       else
         _set_content_type _get_content_type(rendered_format)
       end
diff --git a/actionpack/test/controller/new_base/render_html_test.rb b/actionpack/test/controller/new_base/render_html_test.rb
index 49c1b67d04218..e9ea57e329b63 100644
--- a/actionpack/test/controller/new_base/render_html_test.rb
+++ b/actionpack/test/controller/new_base/render_html_test.rb
@@ -4,7 +4,6 @@ module RenderHtml
   class MinimalController < ActionController::Metal
     include AbstractController::Rendering
     include ActionController::Rendering
-    include ActionView::Rendering
 
     def index
       render html: "Hello World!"