Added carboard-java library to third_party

third_party/cardboard-java/BUILD.gn

Index: third_party/cardboard-java/BUILD.gn
diff --git a/third_party/cardboard-java/BUILD.gn b/third_party/cardboard-java/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..a6ff1b6cea8b272159d41b399b26bf2f32d19b92
--- /dev/null
+++ b/third_party/cardboard-java/BUILD.gn
@@ -0,0 +1,13 @@
+# 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/android/rules.gni")
+
+# GYP: //third_party/cardboard-java/cardboard.gyp:cardboard_jar
+java_prebuilt("cardboard-java") {
+  jar_path = "src/CardboardSample/libs/cardboard.jar"
+  deps = [
+    "//third_party/android_protobuf/android_protobuf.gyp:protobuf_nano_javalib",
+  ]
+}