Transcoder: Add a MediaSampleReader benchmark test.

Test non-sequential sample access as well as sequential
video only access.

Test: Ran the benchmark.
Bug: 160268606
Bug: 152091444
Change-Id: I6407c8011e85e2b5050450f76f24289009995d1e
diff --git a/media/libmediatranscoding/transcoder/benchmark/Android.bp b/media/libmediatranscoding/transcoder/benchmark/Android.bp
index 507c943..b755206 100644
--- a/media/libmediatranscoding/transcoder/benchmark/Android.bp
+++ b/media/libmediatranscoding/transcoder/benchmark/Android.bp
@@ -4,3 +4,11 @@
     shared_libs: ["libmediatranscoder", "libmediandk"],
     static_libs: ["libgoogle-benchmark"],
 }
+
+cc_test {
+    name: "MediaSampleReaderBenchmark",
+    srcs: ["MediaSampleReaderBenchmark.cpp"],
+    shared_libs: ["libmediatranscoder", "libmediandk", "libbase"],
+    static_libs: ["libgoogle-benchmark"],
+}
+