Mac: Fix bookmark button drawing regression

Mac: Fix bookmark button drawing regression

When the bookmark bar is hidden, BookmarkBarToolbarView's height
is set to 0.
Before https://crrev.com/924143002/, when BookmarkButton calls its
drawRect through cr_drawUsingAncestor, it was filling its bounds,
effectively drawing nothing.
After the change, it was filling |dirtyRect|, so it was drawing the SHOW
state even though its bounds has 0 height.
The whole thing is fragile and can probably be done better, but we should
not ask the ancestor to draw outside its bounds anyway, thus this fix.

BUG=459992
Committed: https://crrev.com/489df883d4431e11e72d5007eda8f8de7f129f46
Cr-Commit-Position: refs/heads/master@{#317693}

[Andre, 2015-02-23 22:53:15]

andresantoso@chromium.org changed reviewers:
+ rsesek@chromium.org

[Andre, 2015-02-23 22:53:15]

Robert, please review.

[Robert Sesek, 2015-02-24 00:06:51]

lgtm

[Andre, 2015-02-24 00:22:33]

The CQ bit was checked by andresantoso@chromium.org

[commit-bot: I haz the power, 2015-02-24 00:24:18]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/951063002/1

[commit-bot: I haz the power, 2015-02-24 00:41:29]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-02-24 00:42:04]

Patchset 1 (id:??) landed as
https://crrev.com/489df883d4431e11e72d5007eda8f8de7f129f46
Cr-Commit-Position: refs/heads/master@{#317693}