trancoding: lazy-start transcoding service

bug: 186387244
test: atest MediaTranscodeManagerTest; unit tests
Change-Id: I80bb476abf919b908ac9b79c32b09bdc90876cf0
diff --git a/services/mediatranscoding/tests/MediaTranscodingServiceTestHelper.h b/services/mediatranscoding/tests/MediaTranscodingServiceTestHelper.h
index 20e4bfb..0cb2fad 100644
--- a/services/mediatranscoding/tests/MediaTranscodingServiceTestHelper.h
+++ b/services/mediatranscoding/tests/MediaTranscodingServiceTestHelper.h
@@ -481,7 +481,7 @@
         // Need thread pool to receive callbacks, otherwise oneway callbacks are
         // silently ignored.
         ABinderProcess_startThreadPool();
-        ::ndk::SpAIBinder binder(AServiceManager_getService("media.transcoding"));
+        ::ndk::SpAIBinder binder(AServiceManager_waitForService("media.transcoding"));
         mService = IMediaTranscodingService::fromBinder(binder);
         if (mService == nullptr) {
             ALOGE("Failed to connect to the media.trascoding service.");