Don't use legacy layouts for errors (#2517)

The error pages were using the legacy branding and this is very
confusing, especially when shown in the embedded contexts. This change
ensures the error pages are styled like regular pages.

app/controllers/errors_controller.rb

@@ -1,16 +1,43 @@
-class ErrorsController < ApplicationController
-  layout 'error'
+class ErrorsController < EmbeddedToolsController
   before_action :fetch_exception
 
+  layout 'engine_syndicated'
+
   def show
     render :show, status: params[:status_code], formats: [:html]
   end
 
-  def display_skip_to_main_navigation?
-    params[:status_code] != '404'
+  private
+
+  def canonical
+    ''
   end
+  helper_method :canonical
 
-  private
+  def syndicated_tool_request?
+    true
+  end
+  helper_method :syndicated_tool_request?
+
+  def alternate_locale
+    nil
+  end
+  helper_method :alternate_locale
+
+  def alternate_options
+    { 'en-GB' => request.url }
+  end
+  helper_method :alternate_options
+
+  def alternate_url
+    nil
+  end
+  helper_method :alternate_url
+
+  def engine_content?
+    true
+  end
+  helper_method :engine_content?
 
   def fetch_exception
     @exception = env['action_dispatch.exception']

app/views/errors/show.html.erb

@@ -1,22 +1,7 @@
-<% set_meta_tags(title: t(".#{@rescue_response}.title")) %>
-
-<%= heading_tag t(".#{@rescue_response}.heading", default: t('.heading')), class: "error-page__headline" %>
-
-<p class="error-page__text<% if @rescue_response != :not_found %> error-page__text--only<% end %>"><%= t(".#{@rescue_response}.intro", default: t(".#{@rescue_response}.title")) %></p>
-
-<p class="error-page__search-text"><%= t(".#{@rescue_response}.message") %></p>
-
-<form data-dough-component="ClearInput" action="/en/search" method="get" role="search" class="error-page__search search">
-  <label class="visually-hidden" for="search"><%= t('search_box.label') %></label>
-  <input data-dough-clear-input class="search__input" id="search" required type="search" name="query" autocomplete="off" placeholder="<%= t(".#{@rescue_response}.search_placeholder") %>" />
-
-  <button data-dough-clear-input-button type="reset" class="search__clear">
-    <span class="icon icon--clear"></span>
-    <span class="visually-hidden"><%= t('search_box.clear_hidden_text') %></span>
-  </button>
-
-  <button class="search__submit" type="submit">
-    <span class="icon icon--search"></span>
-    <span class="visually-hidden"><%= t('search_box.button_text') %></span>
-  </button>
-</form>
+<% content_for(:engine_content) do %>
+  <div class="global-alert__content-container">
+    <%= heading_tag t(".#{@rescue_response}.heading", default: t('.heading')) %>
+    <p><%= t(".#{@rescue_response}.intro", default: t(".#{@rescue_response}.title")) %></p>
+    <p><%= t(".#{@rescue_response}.message") %></p>
+  </div>
+<% end %>

config/routes.rb

@@ -229,7 +229,7 @@ def not_implemented
     get '/hub/:slug' => 'content_hub#show', as: :content_hub
   end
 
-  %w(422 500 ).each do |status_code|
+  %w(422 500).each do |status_code|
     get status_code, to: 'errors#show', status_code: status_code
   end