Simplify name joining in make_computed_style_base.py.

Currently, when we wish to combine several strings together to form
the name for a class or data member for example, we have to use
join_name, which would combine the strings correctly in a space
separated format, followed by something like class_member_name that
formats the result into the correct style.

This patch allows things like class_member_name to take a list of
names, and join_name internally.

This does not change behaviour.

Bug: 628043
Change-Id: Iae966e45b9dc80a14bb57cf477af580fb64c85fc
Reviewed-on: https://chromium-review.googlesource.com/532676
Reviewed-by: nainar <nainar@chromium.org>
Commit-Queue: Darren Shen <shend@chromium.org>
Cr-Commit-Position: refs/heads/master@{#487296}
2 files changed