Add BUILD.gn files for chromecast/media

chromecast/media/cma/filters/BUILD.gn

Index: chromecast/media/cma/filters/BUILD.gn
diff --git a/chromecast/media/cma/filters/BUILD.gn b/chromecast/media/cma/filters/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..605075533f9461e32f5ec3ffc1f7c4430f28d63f
--- /dev/null
+++ b/chromecast/media/cma/filters/BUILD.gn
@@ -0,0 +1,20 @@
+# 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.
+
+source_set("filters") {
+  sources = [
+    "cma_renderer.cc",
+    "cma_renderer.h",
+    "demuxer_stream_adapter.cc",
+    "demuxer_stream_adapter.h",
+  ]
+
+  deps = [
+    "//base",
+    "//chromecast/media/cma/base",
+    "//media",
+  ]
+
+  configs += [ "//chromecast:config" ]
+}