mac: Minor tweaks to notifications code.

mac: Minor tweaks to notifications code.

Fixes the lower padding, and simplifies the code a bit.

BUG=none
TEST=Open a notification with more than 2 lines of text. Bottom margin doesn't
look too small.

R=rsesek@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=199777

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=199808

[Nico, 2013-05-12 19:33:50]

Before: http://imgur.com/ymgiZr8,H4aVtOW#1
Now: http://imgur.com/ymgiZr8,H4aVtOW#0

It looks like it was put in deliberately, so it's well possible that this change
is wrong and I'm missing something.

[Robert Sesek, 2013-05-13 15:10:30]

lgtm

[commit-bot: I haz the power, 2013-05-13 15:50:41]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/thakis@chromium.org/14735009/10

[commit-bot: I haz the power, 2013-05-13 17:07:34]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/thakis@chromium.org/14735009/4003

[Nico, 2013-05-13 17:07:36]

(I changed the foreach loop to capture by ref)

[Nico, 2013-05-13 18:38:20]

Committed patchset #3 manually as r199777 (presubmit successful).

[Nico, 2013-05-13 19:57:43]

This got reverted because it broke one of the unit tests. The test checked that
notifications that span 2 lines don't add extra padding, and notifications with
two lines had a few pixels of padding which looked strange.

I looked at the mocks (
https://docs.google.com/a/google.com/file/d/0B5Jnh8WgieufWWpBUUdPX21ycUk/edit )
and it seems to me that the padding constants are between ascender and baseline,
while the nstextfield height is the full font height (see image at
http://developer.apple.com/library/mac/#documentation/TextFonts/Conceptual/Co...
). As a fix, patch set 4 takes ascender and descender into account.
http://imgur.com/xLAQcIL is how it looks; I think it's much closer to the mock.

PTAL.

[Robert Sesek, 2013-05-13 20:02:45]

LGTM. The mocks for the content aren't pixel-perfect yet, so don't feel that
they're locked in. I was just trying to get things close enough to bring up the
core UI components.

[Nico, 2013-05-13 20:12:34]

Committed patchset #4 manually as r199808 (presubmit successful).