Mac Video Capture: Add Blackmagic DeckLink SDK for Mac to third_party folder

third_party/decklink_mac/decklink_mac.gyp

Index: third_party/decklink_mac/decklink_mac.gyp
diff --git a/third_party/decklink_mac/decklink_mac.gyp b/third_party/decklink_mac/decklink_mac.gyp
new file mode 100644
index 0000000000000000000000000000000000000000..198cd3d9132591721e709bf96ea5dc38c3551777
--- /dev/null
+++ b/third_party/decklink_mac/decklink_mac.gyp
@@ -0,0 +1,15 @@
+# Copyright 2014 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+{
+  'targets': [
+    {
+      'target_name': 'decklink_mac',
+      'type': 'static_library',
+      'sources' : [
+        'include/DeckLinkAPIDispatch.cpp',
+      ],
+    },  # target decklink_mac
+  ]
+}