Add BUILD.gn files for chromecast/media

chromecast/media/cma/filters/BUILD.gn

Index: chromecast/media/cma/filters/BUILD.gn
diff --git a/third_party/sudden_motion_sensor/BUILD.gn b/chromecast/media/cma/filters/BUILD.gn
similarity index 53%
copy from third_party/sudden_motion_sensor/BUILD.gn
copy to chromecast/media/cma/filters/BUILD.gn
index 26bdf4284cf7a8b204c21df7562d1deeb9d6f203..e74e9e8d48adc628ca4a6d228dd4a9f927501211 100644
--- a/third_party/sudden_motion_sensor/BUILD.gn
+++ b/chromecast/media/cma/filters/BUILD.gn
@@ -2,13 +2,16 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-source_set("sudden_motion_sensor") {
+component("filters") {
   sources = [
-    "sudden_motion_sensor_mac.cc",
-    "sudden_motion_sensor_mac.h",
+    "cma_renderer.cc",
+    "cma_renderer.h",
+    "demuxer_stream_adapter.cc",
+    "demuxer_stream_adapter.h",
   ]
-
   deps = [
     "//base",
+    "//chromecast/media/cma/base",
+    "//media",
   ]
 }