Revert of Add ui_unittests to GN build.

Revert of Add ui_unittests to GN build. (patchset #2 of https://codereview.chromium.org/496473003/)

Reason for revert:
http://build.chromium.org/p/chromium.chromiumos/builders/Linux%20ChromiumOS%20Ozone%20Builder/builds/2322

Original issue's description:
> Add ui_unittests to GN build.
> 
> Adds os_exchange_data_win_unittest.cc to Windows (it was incorrecly excluded before). Fixed a compilation error in that file.
> 
> Remove special filtering out in GYP build of base/ime/chromeos/character_composer_unittest.cc and base/ime/input_method_chromeos_unittest.cc since the standard filtering patterns match both of these.
> 
> R=sky@chromium.org
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=291154

TBR=sky@chromium.org,brettw@chromium.org
NOTREECHECKS=true
NOTRY=true

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=291181

[rlarocque, 2014-08-21 20:15:23]

Created Revert of Add ui_unittests to GN build.

[commit-bot: I haz the power, 2014-08-21 20:18:23]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/rlarocque@chromium.org/496843002/1

[commit-bot: I haz the power, 2014-08-21 20:56:00]

Committed patchset #1 (1) as 291181