Is anyone working on it? If not, may I look into it?
I'm waiting resoving the spec.

I have been fixing https://codereview.chromium.org/2709763004/(Make WebkitCSSMatrix an alias as of DOMMatrix that has been waiting for fixing other spec issue.
It is from the issue, and the spec is resolved. 
So I want to fix it asap :)

 Issue 716178  has been merged into this issue.

Just an update. This work is already in on https://codereview.chromium.org/2859293002, but we are having some issues with the WPT that I'd like to solve first.

If we can't solve them by tomorrow, I'll submit it anyway.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/6156f7b21c2555d4ce52cecff7f5851ebb57652e

commit 6156f7b21c2555d4ce52cecff7f5851ebb57652e
Author: fserb <fserb@chromium.org>
Date: Thu May 11 05:45:21 2017

Use union instead of overload fo DOMMatrix/DOMMatrixReadOnly

Fixes DOMMatrix-001 tests that were just broken as written (missing brackets)

BUG= 716169 

Review-Url: https://codereview.chromium.org/2859293002
Cr-Commit-Position: refs/heads/master@{#470827}

[modify] https://crrev.com/6156f7b21c2555d4ce52cecff7f5851ebb57652e/third_party/WebKit/LayoutTests/external/wpt/css/geometry-1/DOMMatrix-001-expected.txt
[modify] https://crrev.com/6156f7b21c2555d4ce52cecff7f5851ebb57652e/third_party/WebKit/LayoutTests/external/wpt/css/geometry-1/DOMMatrix-001.html
[modify] https://crrev.com/6156f7b21c2555d4ce52cecff7f5851ebb57652e/third_party/WebKit/Source/bindings/core/v8/BUILD.gn
[modify] https://crrev.com/6156f7b21c2555d4ce52cecff7f5851ebb57652e/third_party/WebKit/Source/core/geometry/DOMMatrix.cpp
[modify] https://crrev.com/6156f7b21c2555d4ce52cecff7f5851ebb57652e/third_party/WebKit/Source/core/geometry/DOMMatrix.h
[modify] https://crrev.com/6156f7b21c2555d4ce52cecff7f5851ebb57652e/third_party/WebKit/Source/core/geometry/DOMMatrix.idl
[modify] https://crrev.com/6156f7b21c2555d4ce52cecff7f5851ebb57652e/third_party/WebKit/Source/core/geometry/DOMMatrixReadOnly.cpp
[modify] https://crrev.com/6156f7b21c2555d4ce52cecff7f5851ebb57652e/third_party/WebKit/Source/core/geometry/DOMMatrixReadOnly.h
[modify] https://crrev.com/6156f7b21c2555d4ce52cecff7f5851ebb57652e/third_party/WebKit/Source/core/geometry/DOMMatrixReadOnly.idl

Aaaaaand we are out! :)