Fix clang-tidy warnings in audio and playerservice.

* Add explicit keyword to conversion constructors.
Bug: 28341362
* Use const reference type for read-only parameters.
Bug: 30407689
Test: build with WITH_TIDY=1

Change-Id: I265f3b094e08d5705b506b3fbba51439c134af84
Merged-In: I265f3b094e08d5705b506b3fbba51439c134af84
diff --git a/media/libmediaplayerservice/MediaPlayerService.cpp b/media/libmediaplayerservice/MediaPlayerService.cpp
index 4ec2ac4..95ed486 100644
--- a/media/libmediaplayerservice/MediaPlayerService.cpp
+++ b/media/libmediaplayerservice/MediaPlayerService.cpp
@@ -307,7 +307,7 @@
     return recorder;
 }
 
-void MediaPlayerService::removeMediaRecorderClient(wp<MediaRecorderClient> client)
+void MediaPlayerService::removeMediaRecorderClient(const wp<MediaRecorderClient>& client)
 {
     Mutex::Autolock lock(mLock);
     mMediaRecorderClients.remove(client);
@@ -548,7 +548,7 @@
     return NO_ERROR;
 }
 
-void MediaPlayerService::removeClient(wp<Client> client)
+void MediaPlayerService::removeClient(const wp<Client>& client)
 {
     Mutex::Autolock lock(mLock);
     mClients.remove(client);