[GN build] Add a BUILD.gn file for //third_party/decklink

[GN build] Add a BUILD.gn file for //third_party/decklink

BUG=none
TEST=none
R=jamesr@chromium.org
TBR=perkj@chromium.org
NOPRESUBMIT=true
NOTRY=true

Committed: https://crrev.com/8652b92e1a0fbb6716c5b482f38de4ebc8b11157
Cr-Commit-Position: refs/heads/master@{#296141}

[Ilya Sherman, 2014-09-23 00:57:46]

isherman@chromium.org changed reviewers:
+ perkj@chromium.org

[jamesr, 2014-09-23 04:08:18]

lgtm

https://codereview.chromium.org/594653004/diff/20001/third_party/decklink/BUI...
File third_party/decklink/BUILD.gn (right):

https://codereview.chromium.org/594653004/diff/20001/third_party/decklink/BUI...
third_party/decklink/BUILD.gn:6: static_library("decklink") {
can you please add a reference to the gyp equivalent and a backref for gyp? i.e.
something like

# GYP version: third_party/decklink/decklink.gyp:decklink

and in the gyp file

# GN version: //third_party/decklink

it's pretty obvious for trivial cases like this but the markers are useful for
figuring out what's been converted and what to call the target in different
build systems.

[Ilya Sherman, 2014-09-23 04:44:43]

The CQ bit was checked by isherman@chromium.org

[commit-bot: I haz the power, 2014-09-23 04:45:22]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/594653004/40001

[commit-bot: I haz the power, 2014-09-23 04:45:48]

Committed patchset #3 (id:40001) as f20f8b3058c6517c481be8b1012b8c4d681d91f6

[commit-bot: I haz the power, 2014-09-23 04:46:24]

Patchset 3 (id:??) landed as
https://crrev.com/8652b92e1a0fbb6716c5b482f38de4ebc8b11157
Cr-Commit-Position: refs/heads/master@{#296141}