Revert of Remove all reference to carbon api (patchset #2 id:20001 of https://codereview.webrtc.org/2299633002/ )

Reason for revert:
Breaks chromium build

Original issue's description:
> Remove all reference to carbon api
>
> BUG=webrtc:6282
>
> Committed: https://crrev.com/dbd8b6bec4143c940b2f2ca8cd85c25d17327964
> Cr-Commit-Position: refs/heads/master@{#14080}

TBR=magjed@webrtc.org,mflodman@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:6282

Review-Url: https://codereview.webrtc.org/2316563002
Cr-Commit-Position: refs/heads/master@{#14081}

webrtc/modules/desktop_capture/mac/desktop_configuration.h

@@ -12,6 +12,7 @@
 #define WEBRTC_MODULES_DESKTOP_CAPTURE_MAC_DESKTOP_CONFIGURATION_H_
 
 #include <ApplicationServices/ApplicationServices.h>
+#include <Carbon/Carbon.h>
 #include <vector>
 
 #include "webrtc/typedefs.h"
@@ -48,7 +49,7 @@ struct MacDesktopConfiguration {
 
   // Returns the desktop & display configurations in Cocoa-style "bottom-up"
   // (the origin is the bottom-left of the primary monitor, and coordinates
-  // increase as you move up the screen).
+  // increase as you move up the screen) or Carbon-style "top-down" coordinates.
   static MacDesktopConfiguration GetCurrent(Origin origin);
 
   // Returns true if the given desktop configuration equals this one.