transcoding: Rework mediatranscoding test.

Create a sperate directory for all tests associated with
mediatranscoding.
This CL is a preparation of hooking with actual service,
adding perf benchamrk, power measurement.

Bug: 145628554
Test: MediaTranscodingTest.

Change-Id: Ifcdb26eae2e71599e2e19bb92b991f88809ec5e0
diff --git a/media/tests/MediaTranscodingTest/Readme.txt b/media/tests/MediaTranscodingTest/Readme.txt
new file mode 100644
index 0000000..e3b835b
--- /dev/null
+++ b/media/tests/MediaTranscodingTest/Readme.txt
@@ -0,0 +1,8 @@
+MediaTranscodingTest/
+    Uses instrumentation and so can be run with runtest.
+    It assumes /sdcard/media_api/ has been populated.
+
+contents/media_api/
+    Push to /sdcard/media_api/ for use with MediaTranscodingTest:
+    adb shell mkdir /sdcard/media_api
+    adb push contents/media_api/ /sdcard/media_api/