anchor.diff:      url '$urlBase/stable/release/${revisions['stable']}/$ia32File'
       sha256 '${hashes['stable'][ia32File]}'
     end
  +
  +  option 'with-content-shell', 'Download and install content_shell -- headless Dartium for testing'
  +  option 'with-dartium', 'Download and install Dartium -- Chromium with Dart'
   
     devel do
       version '$devVersion'
  
positive.code:   end
  
    def caveats; <<-EOS.undent
       To use with IntelliJ, set the Dartium execute home to:
          #{prefix}/Chromium.app
      EOS
    end
  
negative.code: 
      resource 'content_shell' do
        url '$urlBase/dev/release/${revisions['dev']}/$contentShellFile'
        sha256 '${hashes['dev'][contentShellFile]}'
      end
    end
  
    resource 'content_shell' do
      url '$urlBase/stable/release/${revisions['stable']}/$contentShellFile'
      sha256 '${hashes['stable'][contentShellFile]}'
    end
  
  