A few notes

I've done my best to not make it a hack, but in the end this works on the assumption that I know what the browser is doing and what angular is doing when I think it's doing it, so I guess it's still kinda a hack.

As of July 19th, 2015 it works on Safari, Chrome, and Firefox, and maybe IE but I really don't care to try. It is currently targeted for Angular 1.3. Future plans include providing a minified version via a build process and maybe solving a current issue where only one axis will animate at a time. Since the codebase is small, and due to the nature of it, I will likely not provide test cases, so use it at your own risk. For some information on the implementation read the comments in the source code.

Usage

Simple attach the directive to your container and specify the css class where the transition is defined.

<div resize-animator="my-easing-class">{{ dynamicContent }}</div>

For many the following css will suffice

.my-easing-class {
  -webkit-transition: width 0.3s ease, height 0.3s ease;
     -moz-transition: width 0.3s ease, height 0.3s ease;
       -o-transition: width 0.3s ease, height 0.3s ease;
          transition: width 0.3s ease, height 0.3s ease;
}