MacViews: Get c/b/ui/views/tabs to build on Mac

MacViews: Get c/b/ui/views/tabs to build on Mac

Isolate aura and ash dependencies since they are not included on Mac.
Change GetLocalProcessWindowAtPoint to work with gfx::NativeWindow.
Add window_finder_mac.mm

BUG=425229
Committed: https://crrev.com/48602c37b1f027823b7908080c8e026d5607807f
Cr-Commit-Position: refs/heads/master@{#301235}

[Andre, 2014-10-22 21:15:22]

Patchset #2 (id:20001) has been deleted

[Andre, 2014-10-22 21:15:31]

Patchset #1 (id:1) has been deleted

[Andre, 2014-10-24 20:21:09]

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

[Andre, 2014-10-24 20:22:02]

sky@ PTAL.

[sky, 2014-10-24 22:20:07]

LGTM

[Andre, 2014-10-24 22:28:37]

The CQ bit was checked by andresantoso@chromium.org

[commit-bot: I haz the power, 2014-10-24 22:32:07]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/669243002/60001

[commit-bot: I haz the power, 2014-10-24 23:54:21]

Committed patchset #2 (id:60001)

[commit-bot: I haz the power, 2014-10-24 23:55:25]

Patchset 2 (id:??) landed as
https://crrev.com/48602c37b1f027823b7908080c8e026d5607807f
Cr-Commit-Position: refs/heads/master@{#301235}