include accessibility.css by default but view can choose to not include it

* call disable_accessibility_css! in view to not include css

app/helpers/application_helper.rb

@@ -1146,6 +1146,14 @@ module ApplicationHelper
     @top_menu_split
   end
 
+  def disable_accessibility_css!
+    @accessibility_css_disabled = true
+  end
+
+  def accessibility_css_enabled?
+    !@accessibility_css_disabled
+  end
+
   private
 
   def wiki_helper

app/views/account/login.rhtml

@@ -1,3 +1,5 @@
+<% disable_accessibility_css! %>
+
 <% breadcrumb_paths(l(:label_login)) %>
 <%= call_hook :view_account_login_top %>
 <div id="login-form">

app/views/account/lost_password.rhtml

@@ -1,3 +1,5 @@
+<% disable_accessibility_css! %>
+
 <h2><%=l(:label_password_lost)%></h2>
 
 <div class="box">

app/views/account/password_recovery.rhtml

@@ -1,3 +1,5 @@
+<% disable_accessibility_css! %>
+
 <h2><%=l(:label_password_lost)%></h2>
 
 <%= error_messages_for 'user' %>

app/views/account/register.rhtml

@@ -1,3 +1,5 @@
+<% disable_accessibility_css! %>
+
 <h2><%=l(:label_register)%> <%=link_to l(:label_login_with_open_id_option), signin_url if Setting.openid? %></h2>
 
 <% form_tag({:action => 'register'}, :class => "tabular") do %>

app/views/layouts/base.rhtml

@@ -22,7 +22,7 @@
 <%= javascript_include_tag 'breadcrumb.js' %>
 <%= javascript_include_tag 'chosen.js'%>
 <%= stylesheet_link_tag 'chosen'%>
-<% if User.current.impaired? %>
+<% if User.current.impaired? && accessibility_css_enabled? %>
   <%= stylesheet_link_tag 'accessibility' %>
 <% end %>
 <%= javascript_tag('jQuery.noConflict();') %>