binderwrapper: Resolve ambiguous base::Closure reference

Disambiguate between base and android::base namespaces.  This matters
when headers from libbase are indirectly included.

Bug: 27804373
Test: Compiles in that referenced situation.

Change-Id: Icb26595bb0013733aa8c03971c9f4a950c8b2ab1
diff --git a/libbinderwrapper/stub_binder_wrapper.cc b/libbinderwrapper/stub_binder_wrapper.cc
index 87c6ab7..8e75f62 100644
--- a/libbinderwrapper/stub_binder_wrapper.cc
+++ b/libbinderwrapper/stub_binder_wrapper.cc
@@ -64,7 +64,7 @@
 
 bool StubBinderWrapper::RegisterForDeathNotifications(
     const sp<IBinder>& binder,
-    const base::Closure& callback) {
+    const ::base::Closure& callback) {
   death_callbacks_[binder] = callback;
   return true;
 }