Add a theme-color meta tag to your Drupal site (within your theme's template.php)

gistfile1.php

/*
 * Implements template_preprocess_html()
 * Preprocess variables for the html template file.
 *
 */
function YOUR_THEME_NAME_preprocess_html(&$variables) {
  $android5_theme_color = array(
    '#type' => 'html_tag',
    '#tag' => 'meta',
    '#attributes' => array(
      'name' =>  'theme-color',
      'content' => '#1A237E',
    )
  );
  drupal_add_html_head($android5_theme_color, 'android5_theme_color');
}