[webkit-dev] Chromium Mac moving to Skia

Adam Barth abarth at webkit.org
Wed Sep 21 15:29:42 PDT 2011

To keep everyone updated, here's the latest from Elliot.  The
one-sentence summary is that Chromium Mac will be flipping the switch
to Skia tomorrow.  We'll probably want to keep both sets of baselines
for a couple weeks to make sure the Skia transition sticks, but then
we should be able to remove the CoreGraphics image baselines for
Chromium Mac.

(I've added some notes inline.)


---------- Forwarded message ----------
From: Elliot Poger <epoger at chromium.org>
Date: Wed, Sep 21, 2011 at 3:07 PM
Subject: [chromium-dev] Chromium-on-Mac changing from Core Graphics to
Skia tomorrow
To: Chromium-dev <chromium-dev at chromium.org>

Sometime in the next 24-48 hours, I plan to commit a Chromium change
that will change the default value of "use_skia" on Mac from 0 to 1.
This will cause the default graphics layer on Chromium-for-Mac from
Apple's Core Graphics to our Skia library.
We already use Skia by default for Windows and Linux; this change will
bring Mac in line with those other platforms.
If you run into any problems with this, please let me know... and you
can set use_skia=0 to get the old functionality back (at least until
we are satisfied that Skia is stable and happy).

Additional notes for those who are interested: (links will work for
Googlers only, sorry about that)
This change will cause the accelerated canvas path to be enabled by
default on the Mac.
We have been running the chromium.webkit buildbots against both Skia
and CG for a couple of weeks now.  As of Wednesday afternoon, the Skia
bots have been as green as the CG ones.  (We have marked a lot of
tests as known-to-fail to greenify these tests; the vast majority of
the failures just indicate baselines that need to be regenerated, but
there may be a few real errors lurking in there... we already
corrected some, but there may be more.)

[abarth] http://tinyurl.com/3wdaoqf

[abarth] http://tinyurl.com/3mf9le7

I have a subset of the Chromium buildbots running locally, which I
have been using to compare results with Skia vs CG.  They haven't been
running as long as the chromium.webkit buildbots above, but so far so

[abarth] These don't appear to be visible on the public web.

There are further details about the transition process at
[abarth] This document doesn't appear to be public, probably because
it contains release dates.

On Tue, Aug 16, 2011 at 11:31 AM, Adam Barth <abarth at webkit.org> wrote:
> Hi WebKit,
> In an effort to make the Chromium port more consistent across
> platforms, we're moving the Chromium Mac port from CoreGraphics to
> Skia.  This should mostly have little effect on the rest of the WebKit
> community, but you'll be seeing some patches shortly that shuffle a
> bunch of test expectations around so that we can make the transition
> carefully and avoid regressions.  Specifically, we're planing to do
> the following:
> 1) Move the chromium-mac and chromium-mac-leopard results directories
> to chromium-mac-cg and chromium-mac-cg-leopard, respectively.  This
> will let use keep both CG and Skia results during the transition so
> that we can compare them and avoid regressions.
> 2) Introduce MACCG modifies for test_expectations.  This will let use
> have separate expectations for CG and Skia.
> 3) Introduce new chromium-mac and chromium-mac-leopard results
> directories, which will correspond to the new Skia configuration.
> 4) Move the Chromium Mac builders on build.webkit.org over to using
> the Skia configuration.
> Two of these steps will generate somewhat large svn update steps.  I'd
> like to thank you in advance for being patient with us as we make this
> transition.  If you have any questions or concerns, please feel to
> respond to this thread or to ask Cary or myself.
> Thanks again,
> Adam

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