src/main/resources/static/chromium-style.html

<dom-module id="chromium-style">
  <script>
    Gerrit.install(function(plugin) {
      plugin.registerStyleModule(
          'change-metadata', 'chromium-style-change-metadata');
      switch (window.location.host) {
        case 'chromium-review.googlesource.com':
        case 'canary-chromium-review.googlesource.com':
          plugin.registerStyleModule('app-theme', 'chromium-style-chromium');
          break;
        case 'chrome-internal-review.googlesource.com':
        case 'canary-chrome-internal-review.googlesource.com':
          plugin.registerStyleModule('app-theme', 'chromium-style-chrome');
          break;
      }
    });
  </script>
</dom-module>

<dom-module id="chromium-style-chromium">
  <style>
    :root {
      --header-background-color: #DCE5F8;
      --header-title-content: "Chromium Gerrit";
      --header-icon: url("chromium_logo.png");
      --header-icon-size: 1em;
    }
  </style>
</dom-module>

<dom-module id="chromium-style-chrome">
  <style>
    :root {
      --header-background-color: #F5CFCC;
      --header-title-content: "Chrome Internal Gerrit";
      --header-icon: url("chrome_logo.png");
      --header-icon-size: 1em;
    }
  </style>
</dom-module>

<dom-module id="chromium-style-change-metadata">
  <style>
    html {
      --change-metadata-assignee: {
        display: none;
      }
      --change-metadata-label-status: {
        display: none;
      }
      --change-metadata-strategy: {
        display: none;
      }
      --change-metadata-topic: {
        display: none;
      }
    }
  </style>
</dom-module>