A few outcomes:
- SourceMaps are unreliable, e.g. CSS post-processing breaks source maps (https://github.com/postcss/postcss/issues/797)
- SASS syntax supports variables as a part of property names, which partly breaks sourcemap generation

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/4ded3a7997dfb8307c761f4c38b627a398749f91

commit 4ded3a7997dfb8307c761f4c38b627a398749f91
Author: Andrey Lushnikov <lushnikov@chromium.org>
Date: Thu Nov 09 07:50:33 2017

DevTools: kill LiveSASS experiment

This patch removes the LiveSASS experiment.

Bug:  782935 
Change-Id: Ic69058cb9e0dca6f4305f4730e6334ef67d344e7
Reviewed-on: https://chromium-review.googlesource.com/758752
Commit-Queue: Andrey Lushnikov <lushnikov@chromium.org>
Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#515119}
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Why removed this function? Which is very useful for developers. The PostCSS problem should be solved by PostCSS itself, and the author also has plans to support it in the new version.

Is it possible to activate it in some way?