Adding third_party/openh264 build files for encoding

third_party/openh264/openh264_args.gni

Index: third_party/openh264/openh264_args.gni
diff --git a/third_party/openh264/openh264_args.gni b/third_party/openh264/openh264_args.gni
new file mode 100644
index 0000000000000000000000000000000000000000..b7558fbd5bf243a5842737f33b51e1d8ba31cd6d
--- /dev/null
+++ b/third_party/openh264/openh264_args.gni
@@ -0,0 +1,12 @@
+# Copyright 2015 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.
+
+import("//build/config/chrome_build.gni")
+
+declare_args() {
+  # Enable this to build OpenH264 (for encoding, not decoding).
+  # CHECK THE OPENH264 LICENSE/PATENT BEFORE BUILDING, see
+  # http://www.openh264.org/.
+  use_openh264 = false
+}