Because I didn’t!
If you Google “Chrome color picker” get you a bunch of extensions and definitely not obvious information about this wonderful feature. I was recently disappointed by ColorZilla (my previous color picker) because you’re not allowed to use the eye dropper for local files. I stumbled upon this feature in a talk I was watching and even had to go back to see it again to find it (it is also not clear within developer tools). Just click on the color in developer tools and you’ll get a color picker. On the web page, you have an eye dropper. Awesome!
Chrome is seriously proving to be the best front-end development tool. I used to be faithful to Firebug but now Chrome developer tools has my heart.