<!DOCTYPE html>
<script>
    function startTest() {
      if (window.testRunner) {
        testRunner.waitUntilDone();
        testRunner.setBackingScaleFactor(2, finishTest);
      }
    }

    function finishTest() {
      const canvas = document.getElementById('paint');
      canvas.width = 150 * window.devicePixelRatio;
      canvas.height = 150 * window.devicePixelRatio;

      const ctx = canvas.getContext('2d');
      ctx.scale(window.devicePixelRatio, window.devicePixelRatio);

      for (var i = 0; i < 6; i++){
        for (var j = 0; j < 6; j++){
          ctx.fillStyle = 'rgb(' + Math.floor(255 - 42.5 * i) + ',' +
                           Math.floor(255 - 42.5 * j) + ',0)';
          ctx.fillRect(j * 25, i * 25, 25, 25);
        }
      }
      setTimeout(function() { testRunner.notifyDone(); }, 0);
    }
</script>
<body onload="startTest();">
<canvas id="paint" style="width: 150px; height: 150px;" width=150 height=150 ></canvas>

</body>