Change width of element without reflow

I have a music player with an animated bar that displays the current position in the song. It is rendered with requestAnimationFrame and works by changing the width style of the div to X%, where X is the percentage of time through the current song. This causes huge CPU use in Chrome I believe due to the constant reflow work being done each frame. What are other options I can use to eliminate reflo

[efcl]

reflowを起こさずに要素のwidthやheightを変更する方法について