MediaTranscodingService: Rework Service's AIDL.

1) Include parcel in Parcelable's name.
2) Add TranscodingJobPriority.
3) Change registerClient API to include pid, uid and packageName.

Bug:145233472
Test: Build and run.

Change-Id: Ide40e6de8fb1b6f01bbae4577ef3b14d6136b577
diff --git a/services/mediatranscoding/main_mediatranscodingservice.cpp b/services/mediatranscoding/main_mediatranscodingservice.cpp
index 1978eb4..7d862e6 100644
--- a/services/mediatranscoding/main_mediatranscodingservice.cpp
+++ b/services/mediatranscoding/main_mediatranscodingservice.cpp
@@ -29,7 +29,7 @@
     strcpy(argv[0], "media.transcoding");
     sp<ProcessState> proc(ProcessState::self());
     sp<IServiceManager> sm = defaultServiceManager();
-    android::media::MediaTranscodingService::instantiate();
+    android::MediaTranscodingService::instantiate();
 
     ProcessState::self()->startThreadPool();
     IPCThreadState::self()->joinThreadPool();