If you are interested in building Chrome apps, a Google team is working on an IDE. Codenamed Spark it is built with Dart and has a Polymer widgets library

When we reported that Google's Dart Reaches 1.0 last week, we wondered what it might be used for and speculated that

"Chrome is the only browser likely to support a direct implementation". 

The special relationship between Chrome and Dart goes even deeper than you might expect although this isn't too surprising. 

It transpires that one ongoing project being built with Dart is an IDE for Chrome apps with the codename Spark. It's at a very early stage - build version 0.0.15 was released today - and is being worked on by Google's Chromium team, however as an open source project, hosted on GitHub anyone can join in. 

Although you might think that an IDE written in Dart could be made to run on any browser this one makes us of some of the experimental Web Platform features in Chrome. You write the code for the Chrome App in Dart and it gets compiled to JavaScript. 

To draw attention to Spark on Google+, Google engineer Francois Beaufort posted:

This IDE project is full of goodness:

• It is built with Dart, the "new language for scalable web app engineering"
  
  
• It contains a GUI widgets library powered by Polymer
  
  
• It's public on GitHub and therefore interesting for anyone who wants to know how Dart and Polymer can be used to build the next generation of Chrome Apps.

To put this in context, Dart, which recently reached Version 1.0.0  is Google’s open-source Web programming language,  described when it was first announced as a JavaScript killer.

Polymer, which is currently has pre-alpha status  is used in a Dart version:

a new type of library for the web, built on top of Web Components, and designed to leverage the evolving web platform on modern browsers. 

It is used in Mozilla's x-tag library and makes creating web components much easier. In the case of Spark so far there are only three pre-built components ready to use but you can create your own fairly easily. 

Chrome Apps are packaged apps written HTML, JavaScript, and CSS, that launch outside the browser, work offline by default, and access certain APIs, provided by the Chrome host not available to Web apps. They have the advantage that they should work anywhere that the Chrome browser works and could give Chrome a role as a platform.  

It is difficult to know if linking Dart with Chrome and Chrome Apps in particular is more beneficial to Chrome or Dart. One think is certain. It makes the split between Mozilla's web apps and Google's web apps a little big wider.