Transcoding: Log transcoder level metrics.

- Add transcoder-level metric logging through west world,
to monitor performance and failures.

- Add new unit tests for TranscodingLogger class.

Bug: 179274112
Test: New and existing unit tests.
Change-Id: Ie8d9bc589c714a7b8be8f4f298c4fa75a81a6e56
diff --git a/services/mediatranscoding/MediaTranscodingService.h b/services/mediatranscoding/MediaTranscodingService.h
index d024c54..9384641 100644
--- a/services/mediatranscoding/MediaTranscodingService.h
+++ b/services/mediatranscoding/MediaTranscodingService.h
@@ -29,6 +29,7 @@
 using ::aidl::android::media::TranscodingRequestParcel;
 using ::aidl::android::media::TranscodingSessionParcel;
 class TranscodingClientManager;
+class TranscodingLogger;
 class TranscodingSessionController;
 class UidPolicyInterface;
 class ResourcePolicyInterface;
@@ -62,6 +63,7 @@
     std::shared_ptr<UidPolicyInterface> mUidPolicy;
     std::shared_ptr<ResourcePolicyInterface> mResourcePolicy;
     std::shared_ptr<ThermalPolicyInterface> mThermalPolicy;
+    std::shared_ptr<TranscodingLogger> mLogger;
     std::shared_ptr<TranscodingSessionController> mSessionController;
     std::shared_ptr<TranscodingClientManager> mClientManager;
 };