Group of overlapping elements with SVG background

[Mire]

Test case description

Set a background color for the SVG.
Create a group element containing two overlapping rect elements, each filled with a different solid color.
Apply a mix-blend-mode other than normal on the group.

For details about the notations and more in-context information please refer to section mix-blend-mode with SVG groups of the test plan:
http://mire.github.io/css-blending-test-plan-proposal/css-blending-test-plan-proposal.html

Expected result

The group is mixed as a whole with the color of the background.

W3C specification

This test case pertains to the following w3c specification:
http://www.w3.org/TR/compositing-1/

[wpt-issue-mover]

This issue has been merged into web-platform-tests/wpt#5555; please see that issue if you wish to discuss or work on this.