title: Make some gradient move endlessly in a progress bar like in Windows 7
body: <p>I wonder if it's possible to make a gradient move inside a div from left to right endlessly using only CSS3 features? There is no need to support all browsers, I just want to experiment.
  The example is that shiny effect on top of the blue progress bar. An example is appreciated.</p>
  
  <p><img src="https://i.stack.imgur.com/CUbLS.png" alt="enter image description here"></p>