Change meta tag theme color to match theme

Changes the hardcoded theme-color meta tag
to match the primary color from the users selected theme.

Changelog: fixed

app/helpers/preferences_helper.rb

@@ -66,6 +66,10 @@ module PreferencesHelper
     @user_application_theme_css_filename ||= Gitlab::Themes.for_user(current_user).css_filename
   end
 
+  def user_theme_primary_color
+    Gitlab::Themes.for_user(current_user).primary_color
+  end
+
   def user_color_scheme
     Gitlab::ColorSchemes.for_user(current_user).css_class
   end

app/views/layouts/_head.html.haml

@@ -71,7 +71,7 @@
   = action_cable_meta_tag
 
   %meta{ name: 'viewport', content: 'width=device-width, initial-scale=1, maximum-scale=1' }
-  %meta{ name: 'theme-color', content: '#474D57' }
+  %meta{ name: 'theme-color', content: user_theme_primary_color }
 
   -# Apple Safari/iOS home screen icons
   = favicon_link_tag 'touch-icon-iphone.png', rel: 'apple-touch-icon'

lib/gitlab/themes.rb

@@ -10,21 +10,21 @@ module Gitlab
     APPLICATION_DEFAULT = 1
 
     # Struct class representing a single Theme
-    Theme = Struct.new(:id, :name, :css_class, :css_filename)
+    Theme = Struct.new(:id, :name, :css_class, :css_filename, :primary_color)
 
     # All available Themes
     THEMES = [
-      Theme.new(1, 'Indigo', 'ui-indigo', 'theme_indigo'),
-      Theme.new(6, 'Light Indigo', 'ui-light-indigo', 'theme_light_indigo'),
-      Theme.new(4, 'Blue', 'ui-blue', 'theme_blue'),
-      Theme.new(7, 'Light Blue', 'ui-light-blue', 'theme_light_blue'),
-      Theme.new(5, 'Green', 'ui-green', 'theme_green'),
-      Theme.new(8, 'Light Green', 'ui-light-green', 'theme_light_green'),
-      Theme.new(9, 'Red', 'ui-red', 'theme_red'),
-      Theme.new(10, 'Light Red', 'ui-light-red', 'theme_light_red'),
-      Theme.new(2, 'Dark', 'ui-dark', 'theme_dark'),
-      Theme.new(3, 'Light', 'ui-light', 'theme_light'),
-      Theme.new(11, 'Dark Mode (alpha)', 'gl-dark', nil)
+      Theme.new(1, 'Indigo', 'ui-indigo', 'theme_indigo', '#292961'),
+      Theme.new(6, 'Light Indigo', 'ui-light-indigo', 'theme_light_indigo', '#4b4ba3'),
+      Theme.new(4, 'Blue', 'ui-blue', 'theme_blue', '#1a3652'),
+      Theme.new(7, 'Light Blue', 'ui-light-blue', 'theme_light_blue', '#2261a1'),
+      Theme.new(5, 'Green', 'ui-green', 'theme_green', '#0d4524'),
+      Theme.new(8, 'Light Green', 'ui-light-green', 'theme_light_green', '#156b39'),
+      Theme.new(9, 'Red', 'ui-red', 'theme_red', '#691a16'),
+      Theme.new(10, 'Light Red', 'ui-light-red', 'theme_light_red', '#a62e21'),
+      Theme.new(2, 'Dark', 'ui-dark', 'theme_dark', '#303030'),
+      Theme.new(3, 'Light', 'ui-light', 'theme_light', '#666'),
+      Theme.new(11, 'Dark Mode (alpha)', 'gl-dark', nil, '#303030')
     ].freeze
 
     # Convenience method to get a space-separated String of all the theme