Revert of mac: Fix tab dragging visual bug in Yosemite. (reland) (https://codereview...

Revert of mac: Fix tab dragging visual bug in Yosemite. (reland) (https://codereview.chromium.org/393933003/)

Reason for revert:
Broke TestActivate and TestFullscreen on Mac 10.6 Tests (http://build.chromium.org/p/chromium.mac/builders/Mac10.6%20Tests%20%282%29/builds/53658)

Original issue's description:
> 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.
>
link: https://codereview.chromium.org/379293003/
> BUG=392239
>
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=283456

TBR=andresantoso@chromium.org,shess@chromium.org,erikchen@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=392239

Review URL: https://codereview.chromium.org/398903003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@283563 0039d316-1c4b-4281-b951-d872f2087c98