Fix google-explicit-constructor warnings.

Bug: 28341362
Change-Id: I625fbab25f16282c2ea929cd16283d9d146fa17b
diff --git a/media/libmedia/IResourceManagerService.cpp b/media/libmedia/IResourceManagerService.cpp
index 4598686..c4cded0 100644
--- a/media/libmedia/IResourceManagerService.cpp
+++ b/media/libmedia/IResourceManagerService.cpp
@@ -58,7 +58,7 @@
 class BpResourceManagerService : public BpInterface<IResourceManagerService>
 {
 public:
-    BpResourceManagerService(const sp<IBinder> &impl)
+    explicit BpResourceManagerService(const sp<IBinder> &impl)
         : BpInterface<IResourceManagerService>(impl)
     {
     }