canvas.toDataURL throwing DOM exception 18 on data src images

[emepyc]

The following script:

var page = require('webpage').create();

page.evaluate(function() {
    var svg = '<svg class="tnt_tracks_svg" width="800" height="180" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/\
xlink"><rect width="10" height="10" fill="red"></rect></svg>';

    var src = 'data:image/svg+xml;base64,' + window.btoa(unescape(encodeURIComponent(svg)));

    var img = new Image();
    img.src = src;
    img.onload = function() {
        var canvas = document.createElement('canvas');
        canvas.width = img.width;
        canvas.height = img.height;
        var context = canvas.getContext('2d');
        context.drawImage(img, 0, 0);
        var src = canvas.toDataURL(); // DOM Exception 18!
    }
});

Throws a DOM exception 18. The image src is passed as data, so no cross-domain violation should be triggered. Using '--web-security=false' doesn't solve the problem.
Tested on phantomjs version 1.9.7

[stale]

Due to our very limited maintenance capacity (see #14541 for more details), we need to prioritize our development focus on other tasks. Therefore, this issue will be automatically closed. In the future, if we see the need to attend to this issue again, then it will be reopened. Thank you for your contribution!