[Skia] Update SkiaImageFilterBuilder's brightness matrix to match Chromium's implementation
https://bugs.webkit.org/show_bug.cgi?id=107841

Reviewed by Stephen White.

Update Skia's brightness filter to match the spec after http://trac.webkit.org/changeset/139770.

No new tests: covered by existing tests (currently disabled pending rebaseline).

* platform/graphics/filters/skia/SkiaImageFilterBuilder.cpp:


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@141427 268f45cc-cd09-0410-ab3c-d52691b4dbfc