mac: Fix tab dragging visual bug in Yosemite. (reland)

mac: Fix tab dragging visual bug in Yosemite. (reland)

-----------------Reland Description------------------
Core animation was turned on in M35. The fullscreen window was not layer
backed, but should have been. This original CL exposed this bug.

-----------------Original Description------------------
In OSX 10.10+, all views must be added to the NSWindow's contentView. Some
views (like the tab strip and the profile icon) are placed on top of the title
bar and require special treatment. All other views are added as subviews of
'chromeContentView' in TabWindowController. This allows tab dragging and
fullscreen logic to easily move the views that don't need special treatment.

This CL also removes the instances where a VersionIndependentWindow's
contentView gets replaced by setContentView:. Instead, the 'chromeContentView'
gets passed around as a subview. This allows VersionIndependentWindow to remove
another of its internal hacks.

Original CL link: https://codereview.chromium.org/379293003/
BUG=392239
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=283456

[erikchen, 2014-07-15 21:06:14]

andresantoso: Please review.

[Andre, 2014-07-15 21:26:52]

lgtm

[erikchen, 2014-07-15 21:28:08]

shess: Please review.

[Scott Hess - ex-Googler, 2014-07-15 21:34:55]

lgtm

[erikchen, 2014-07-15 21:47:52]

The CQ bit was checked by erikchen@chromium.org

[commit-bot: I haz the power, 2014-07-15 21:51:04]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/erikchen@chromium.org/393933003/20001

[commit-bot: I haz the power, 2014-07-16 05:22:41]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  android_dbg_triggered_tests on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/android_dbg_triggered...)

[commit-bot: I haz the power, 2014-07-16 05:43:27]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-07-16 05:43:28]

Try jobs failed on following builders:
  android_dbg_triggered_tests on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/android_dbg_triggered...)

[erikchen, 2014-07-16 15:32:14]

The CQ bit was checked by erikchen@chromium.org

[commit-bot: I haz the power, 2014-07-16 15:34:15]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/erikchen@chromium.org/393933003/20001

[commit-bot: I haz the power, 2014-07-16 18:54:03]

Change committed as 283456

[agable, 2014-07-16 22:08:55]

A revert of this CL has been created in
https://codereview.chromium.org/398903003/ by agable@chromium.org.

The reason for reverting is: Broke TestActivate and TestFullscreen on Mac 10.6
Tests
(http://build.chromium.org/p/chromium.mac/builders/Mac10.6%20Tests%20%282%29/b...).