Merge branch 'compare-code-view' into 'master'

Apply diff view cookie on compare

## What does this MR do?

Correctly respects the code view changing when comparing 2 refs.

## What are the relevant issue numbers?

Closes #19573 

## Screenshots (if relevant)

![Screen_Shot_2016-07-07_at_12.38.07](/uploads/b6da78cc2bbc2c79dbe8292037176c1a/Screen_Shot_2016-07-07_at_12.38.07.png)

![Screen_Shot_2016-07-07_at_12.38.17](/uploads/977f8b697c65bdb1701db11a39287ac6/Screen_Shot_2016-07-07_at_12.38.17.png)

See merge request !5135

CHANGELOG

@@ -56,6 +56,7 @@ v 8.10.0 (unreleased)
   - The Markdown reference parsers now re-use query results to prevent running the same queries multiple times !5020
   - Updated project header design
   - Issuable collapsed assignee tooltip is now the users name
+  - Fix compare view not changing code view rendering style
   - Exclude email check from the standard health check
   - Updated layout for Projects, Groups, Users on Admin area !4424
   - Fix changing issue state columns in milestone view

app/controllers/projects/compare_controller.rb

@@ -15,6 +15,7 @@ class Projects::CompareController < Projects::ApplicationController
   end
 
   def show
+    apply_diff_view_cookie!
   end
 
   def diff_for_path