Yesterday, Google has launched Web Designer  ( beta version) , a new tool for building interactive HTML5 sites. Web Designer, which Google calls a “professional-quality design tool,” is now officially in public beta and available for download for Mac and Windows.

In beta version, Google Web Designer is supporting : Google Ads (both for mobile ads and generic), HTML, CSS, Javascript, XML.

The default layout:

Code view layout:

Preview select box : You can choose all of installed browsers.

Publish screen:

Some demos  for Web Designer from Youtube :

1.UI overview demo

2. Pen tool demo
I think Google Web designer will help Pro developers and designers work better and faster. It's also help somebody who's not good at design can work better.