Add script to remove prefixed CSS from third_party/polymer.

Add script to remove prefixed CSS from third_party/polymer.

BUG=
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

[Dan Beam, 2016-01-26 17:22:17]

dbeam@chromium.org changed reviewers:
+ dbeam@chromium.org

[Dan Beam, 2016-01-26 17:22:18]

we depend on node because polymer does, but the fact that
bower/crisper/vulcanize are written in node doesn't really matter to me.  they
could be written in python instead (and in fact: the tracing team ported to
python), but as long as the way we invoke them still works, we're all good. 
fwiw: I didn't think of the bower/crisper process, and I'm not happy with the
vulcanize one.

you've intentionally written this as a node script even though I asked you do
this in python instead.  there's basically 0 advantage to doing this in node
currently.  all of our tooling is in python (generally) and you're just doing
basic string manipulation/regexes.

not lgtm until you get a consensus from chromium-dev@ that writing node scripts
is OK

[Dan Beam, 2016-01-26 17:31:46]

https://codereview.chromium.org/1633603004/diff/40001/third_party/polymer/v1_...
File third_party/polymer/v1_0/css_strip_prefixes.js (right):

https://codereview.chromium.org/1633603004/diff/40001/third_party/polymer/v1_...
third_party/polymer/v1_0/css_strip_prefixes.js:30: var prefixRegex = new
RegExp(/-webkit-|-moz-|-ms-/);
new RegExp(/regexLiteral/) makes very little sense.  it should probably just be
/regexLiteral/

https://codereview.chromium.org/1633603004/diff/40001/third_party/polymer/v1_...
third_party/polymer/v1_0/css_strip_prefixes.js:34: new
RegExp(/@-webkit-keyframes/),
why are you removing this?

https://codereview.chromium.org/1633603004/diff/40001/third_party/polymer/v1_...
third_party/polymer/v1_0/css_strip_prefixes.js:88: }, []);
I have no idea what this code does, frankly, but the major problem is this:

#rule {
  -webkit-border-radius: 5px;
}

if you strip that ^ rule, you lose a style.

#rule {
  -webkit-border-radius: 5px;
  border-radius: 5px;
}

if you strip the -webkit one ^ here, you have the same style with less cruft.

so you basically need to end up writing a map of

_EXACTLY_EQUIVALENT_PREFIXED_RULES = {
  '-webkit-border-radius': 'border-radius',
}

and make sure that you only strip in the case that you're sure something doesn't
get messed up.

oh yeah: and pray that you don't tickle cases where the prefixed and unprefixed
versions aren't subtly different, as well as handle when shorthands and
"longhands"(?) override eachother in the same rule.

[Dan Beam, 2016-08-12 03:38:04]

Description was changed from

==========
Add script to remove prefixed CSS from third_party/polymer.

BUG=
==========

to

==========
Add script to remove prefixed CSS from third_party/polymer.

BUG=
==========

[dpapad, 2017-03-20 22:48:18]

Description was changed from

==========
Add script to remove prefixed CSS from third_party/polymer.

BUG=
==========

to

==========
Add script to remove prefixed CSS from third_party/polymer.

BUG=
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation
==========