libmediaplayerservice: fix warnings, make warnings errors, use clang

Change-Id: I1b2f6b65c5abbc366068a60b8909104f31b94228
diff --git a/media/libmediaplayerservice/MetadataRetrieverClient.cpp b/media/libmediaplayerservice/MetadataRetrieverClient.cpp
index 80804a7..6ef4c1f 100644
--- a/media/libmediaplayerservice/MetadataRetrieverClient.cpp
+++ b/media/libmediaplayerservice/MetadataRetrieverClient.cpp
@@ -57,7 +57,7 @@
     disconnect();
 }
 
-status_t MetadataRetrieverClient::dump(int fd, const Vector<String16>& /*args*/) const
+status_t MetadataRetrieverClient::dump(int fd, const Vector<String16>& /*args*/)
 {
     const size_t SIZE = 256;
     char buffer[SIZE];