Transcoder: Added MediaTranscoder and unit test.

MediaTranscoder is the API for the native transcoding library.

Test: Unit tests.
Bug: 156003955, 152091443, 155918341
Change-Id: I24b52d174db0faecea8f331ef6d8a3dc4e473c4e
diff --git a/media/libmediatranscoding/transcoder/tests/VideoTrackTranscoderTests.cpp b/media/libmediatranscoding/transcoder/tests/VideoTrackTranscoderTests.cpp
index 3cec1a1..6b1f640 100644
--- a/media/libmediatranscoding/transcoder/tests/VideoTrackTranscoderTests.cpp
+++ b/media/libmediatranscoding/transcoder/tests/VideoTrackTranscoderTests.cpp
@@ -100,10 +100,11 @@
     EXPECT_EQ(transcoder.configure(mMediaSampleReader, mTrackIndex, mDestinationFormat), AMEDIA_OK);
     ASSERT_TRUE(transcoder.start());
 
-    std::thread sampleConsumerThread{[&transcoder] {
+    std::shared_ptr<MediaSampleQueue> outputQueue = transcoder.getOutputQueue();
+    std::thread sampleConsumerThread{[&outputQueue] {
         uint64_t sampleCount = 0;
         std::shared_ptr<MediaSample> sample;
-        while (!transcoder.mOutputQueue.dequeue(&sample)) {
+        while (!outputQueue->dequeue(&sample)) {
             ASSERT_NE(sample, nullptr);
             const uint32_t flags = sample->info.flags;