[webkit-reviews] review requested: [Bug 24101] Chromium Windows port should support semitransparent ClearType fonts : [Attachment 27891] Patch

[bugzilla-daemon at webkit.org]

Brett Wilson (Google) <brettw at chromium.org> has asked  for review:
Bug 24101: Chromium Windows port should support semitransparent ClearType fonts
https://bugs.webkit.org/show_bug.cgi?id=24101

Attachment 27891: Patch
https://bugs.webkit.org/attachment.cgi?id=27891&action=review

------- Additional Comments from Brett Wilson (Google) <brettw at chromium.org>
Fix Windows transparency for the Chromium port. Implement a helper class for
handling transparency on Windows. It allows semitransparent ClearType and
semitransparent form controls by making new layers in the background. 

It also replaces the "ThemeHelper" which allows better scaling and transforms
on Windows form controls. In addition to the functionality that the ThemeHelper
did, but additionally handles the antialiasing properly so that the form
controls aren't composited on a white square.

This is covered by layout tests that previously had wrong results (requires
re-baselining 71 Chromium-specific results, note that the Chromium layout test
results are currently only in the Chromium tree). However, the majority of the
layout test changes are a result of me now enabling filtering for more types of
bitmap drawing that previously looked bad (this is what this patch uses to draw
form controls transformed).

There is also a Google-style unit test for some of the basic functionality.
This is a lower-level test than the layout tests that I used when developing
this patch. You can see it here:
http://codereview.chromium.org/21201/diff/5121/5140