i will take this issue.

Thanks! Just so we don't clash, I'm adding layout tests for CSSScale and CSSRotation as part of  crbug.com/774887 . The patches should land soon.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/f0cf6b28ead34d3b46a4f1a24a1931e867dd454a

commit f0cf6b28ead34d3b46a4f1a24a1931e867dd454a
Author: Hwanseung Lee <hs1217.lee@samsung.com>
Date: Tue Nov 21 14:01:59 2017

[css-typed-om] CSSScale should take Numberishes

CSSScale currently only takes doubles,
but it should take Numberishes.
so replace double with Numberish at CSSScale.

https://drafts.css-houdini.org/css-typed-om-1/#cssscale

Bug:  784218 
Change-Id: I11c9e98a0c9468ecbdc82338d081b60918caa456
Reviewed-on: https://chromium-review.googlesource.com/766227
Commit-Queue: Hwanseung Lee <hs1217.lee@samsung.com>
Reviewed-by: Darren Shen <shend@chromium.org>
Cr-Commit-Position: refs/heads/master@{#518238}
[modify] https://crrev.com/f0cf6b28ead34d3b46a4f1a24a1931e867dd454a/third_party/WebKit/LayoutTests/typedcssom/cssScale.html
[modify] https://crrev.com/f0cf6b28ead34d3b46a4f1a24a1931e867dd454a/third_party/WebKit/LayoutTests/typedcssom/stylevalue-subclasses/cssScale-expected.txt
[modify] https://crrev.com/f0cf6b28ead34d3b46a4f1a24a1931e867dd454a/third_party/WebKit/LayoutTests/typedcssom/stylevalue-subclasses/cssScale.html
[modify] https://crrev.com/f0cf6b28ead34d3b46a4f1a24a1931e867dd454a/third_party/WebKit/Source/core/css/cssom/CSSScale.cpp
[modify] https://crrev.com/f0cf6b28ead34d3b46a4f1a24a1931e867dd454a/third_party/WebKit/Source/core/css/cssom/CSSScale.h
[modify] https://crrev.com/f0cf6b28ead34d3b46a4f1a24a1931e867dd454a/third_party/WebKit/Source/core/css/cssom/CSSScale.idl
[modify] https://crrev.com/f0cf6b28ead34d3b46a4f1a24a1931e867dd454a/third_party/WebKit/Source/core/css/cssom/CSSUnitValue.h