BuildLumaHistogram() attempts to access Skia pixel data directly. This isn't

BuildLumaHistogram() attempts to access Skia pixel data directly.  This isn't
correct because the data may need to be unpremultiplied.  Use the appropriate
functions for doing this.

BUG=none
TEST=none
R=erg@chromium.org, reed@google.com, sky@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=202144

[Peter Kasting, 2013-05-23 22:55:48]

This change was not made because I saw a real bug, but rather because I noticed
a theoretical problem while reading the code.

erg: You actually wrote this code back in May 2008 (internally available as
revision 42216).

reed: Advice on whether there is something better we can do than calling
GetColor() in a tight loop would be welcome.

ben: OWNERS.

[reed1, 2013-05-24 11:50:48]

lgtm

I definitely like the change where we don't assume that the pixels are already
in SkColor format, but are calling getColor() instead.

[Elliot Glaysher, 2013-05-24 17:59:10]

lgtm

[sky, 2013-05-24 19:23:32]

LGTM

[Peter Kasting, 2013-05-24 19:25:59]

Committed patchset #1 manually as r202144 (presubmit successful).