Add visibility attributes in runtime/p*

Bug: 260881207
Test: presubmit
Test: abtd app_compat_drm
Test: abtd app_compat_top_100
Test: abtd app_compat_banking
Change-Id: Iefca20560bc1753d53e2e1e21daa38c4b6a19fff
diff --git a/runtime/process_state.h b/runtime/process_state.h
index aee200a..94f8bd9 100644
--- a/runtime/process_state.h
+++ b/runtime/process_state.h
@@ -17,7 +17,9 @@
 #ifndef ART_RUNTIME_PROCESS_STATE_H_
 #define ART_RUNTIME_PROCESS_STATE_H_
 
-namespace art {
+#include "base/macros.h"
+
+namespace art HIDDEN {
 
 // The process state passed in from the activity manager, used to determine when to do trimming
 // and compaction.