chromium/src/third_party/blink/web_tests/fast/canvas/canvas-background-alpha.html - manifest_repos/chromium_src - Git at Google

 <!doctype html>
 <style>
 #c {
   background: rgba(0,0,0,0.2);
 }
 </style>
 <canvas id='c' width='300' height='300'>
 <script>
   // bug crbug.com/416174
   var ctx = document.getElementById("c").getContext("2d");
   ctx.clearRect(0,0,150,150);
 </script>
	<!doctype html>
	<style>
	#c {
	background: rgba(0,0,0,0.2);
	}
	</style>
	<canvas id='c' width='300' height='300'>
	<script>
	// bug crbug.com/416174
	var ctx = document.getElementById("c").getContext("2d");
	ctx.clearRect(0,0,150,150);
	</script>