init: log control messages along with the process that sent them

It's currently not clear that init stops processes due to being sent a
control message nor who sent that message.

Bug: 73343913
Test: send control messages and see the logs
Change-Id: I9e9eff2001e649814107ea961b3b747a1f6da598
diff --git a/init/init.h b/init/init.h
index ecce5d7..d4a0e96 100644
--- a/init/init.h
+++ b/init/init.h
@@ -17,6 +17,8 @@
 #ifndef _INIT_INIT_H
 #define _INIT_INIT_H
 
+#include <sys/types.h>
+
 #include <string>
 #include <vector>
 
@@ -36,7 +38,7 @@
 
 Parser CreateParser(ActionManager& action_manager, ServiceList& service_list);
 
-void handle_control_message(const std::string& msg, const std::string& arg);
+void HandleControlMessage(const std::string& msg, const std::string& arg, pid_t pid);
 
 void property_changed(const std::string& name, const std::string& value);