Remove unused mobile mode code (#3206).

Mobile mode was removed in 31e36cf.

app/controllers/application_controller.rb

@@ -172,7 +172,6 @@ class ApplicationController < ActionController::Base
   def reset_current_user
     CurrentUser.user = nil
     CurrentUser.ip_addr = nil
-    CurrentUser.mobile_mode = false
   end
 
   def set_started_at_session

app/logical/current_user.rb

@@ -11,7 +11,6 @@ class CurrentUser
     ensure
       self.user = old_user
       self.ip_addr = old_ip_addr
-      self.mobile_mode = false
     end
   end
 
@@ -49,14 +48,6 @@ class CurrentUser
     Thread.current[:current_ip_addr]
   end
 
-  def self.mobile_mode=(mode)
-    Thread.current[:mobile_mode] = mode
-  end
-
-  def self.mobile_mode?
-    Thread.current[:mobile_mode]
-  end
-
   def self.id
     if user.nil?
       nil

app/models/post.rb

@@ -236,9 +236,7 @@ class Post < ApplicationRecord
     end
 
     def file_url_for(user)
-      if CurrentUser.mobile_mode?
-        large_file_url
-      elsif user.default_image_size == "large" && image_width > Danbooru.config.large_image_width
+      if user.default_image_size == "large" && image_width > Danbooru.config.large_image_width
         large_file_url
       else
         file_url
@@ -246,9 +244,7 @@ class Post < ApplicationRecord
     end
 
     def file_path_for(user)
-      if CurrentUser.mobile_mode?
-        large_file_path
-      elsif user.default_image_size == "large" && image_width > Danbooru.config.large_image_width
+      if user.default_image_size == "large" && image_width > Danbooru.config.large_image_width
         large_file_path
       else
         file_path
@@ -362,7 +358,7 @@ class Post < ApplicationRecord
     end
 
     def image_width_for(user)
-      if CurrentUser.mobile_mode? || user.default_image_size == "large"
+      if user.default_image_size == "large"
         large_image_width
       else
         image_width
@@ -370,7 +366,7 @@ class Post < ApplicationRecord
     end
 
     def image_height_for(user)
-      if CurrentUser.mobile_mode? || user.default_image_size == "large"
+      if user.default_image_size == "large"
         large_image_height
       else
         image_height

app/views/layouts/default.html.erb

@@ -23,7 +23,6 @@
   <meta name="default-image-size" content="<%= CurrentUser.user.default_image_size %>">
   <meta name="enable-auto-complete" content="<%= CurrentUser.user.enable_auto_complete %>">
   <meta name="style-usernames" content="<%= CurrentUser.user.style_usernames? %>">
-  <meta name="mobile-mode" content="<%= CurrentUser.mobile_mode? %>">
   <meta name="last-forum-read-at" content="<%= CurrentUser.user.last_forum_read_at %>">
   <meta name="disable-labeled-saved-searches" content="<%= CurrentUser.disable_categorized_saved_searches? %>">
   <%= content_tag(:meta, nil, name: "disable-mobile-gestures", content: CurrentUser.disable_mobile_gestures?) %>