Move base/mac_util.h to base/mac and use the base::mac namespace....

Move base/mac_util.h to base/mac and use the base::mac namespace.
Fix up callers to use the new location & namespace. Remove includes from 
files where it wasn't necessary.

TEST=it compiles
BUG=none

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=70359

[brettw, 2011-01-01 18:19:34]

TBR

I had to add an additional include to 
chrome/browser/ui/cocoa/chrome_event_processing_window_unittest.mm
to make it compile since it seemed to be getting it implicitly before.

The rest should be just search & replace.

[Avi (use Gerrit), 2011-01-01 21:36:06]

LGTM