Revert of device: Add GN version of the device_unittests target. (patchset #13 id:230001 of https://codereview.chromium.org/912083003/)

Reason for revert:
Mac GN build fails on buildbot:
http://build.chromium.org/p/chromium.mac/builders/Mac%20GN%20%28dbg%29/builds/4172/steps/compile/logs/stdio

Original issue's description:
> device: Add GN version of the device_unittests target.
>
> Tested with the following command lines:
>
> $ gn gen out_gn/Debug
> $ ninja -C out_gn/Debug device_unittests
> $ out_gn/Debug/device_unittests
>
> BUG=None
> TEST=see above
> R=rockot@chromium.org
>
> Committed: https://crrev.com/e16ab4ff264bc3f6c2a850d820b5f5c79fe59d05
> Cr-Commit-Position: refs/heads/master@{#316058}

TBR=rockot@chromium.org,jam@chromium.org,tfarina@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=None

Review URL: https://codereview.chromium.org/924613004

Cr-Commit-Position: refs/heads/master@{#316072}

1 files changed, 0 insertions, 1 deletions

diff --git a/BUILD.gn b/BUILD.gn
index 7dfa0b7..e47ef75 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -261,7 +261,6 @@ group("root") {
   if (!is_android && !is_ios) {
     deps += [
       "//device/usb",
-      "//device:device_unittests",
       "//third_party/pdfium/samples",
     ]
   }