libprocessgroup: Use pid_t consistently for PIDs

Test: m
Change-Id: Ibcef6b73a8fd3088c88b822a6b33d005595488b2
diff --git a/libprocessgroup/task_profiles.h b/libprocessgroup/task_profiles.h
index 25e3a02..a6ce936 100644
--- a/libprocessgroup/task_profiles.h
+++ b/libprocessgroup/task_profiles.h
@@ -185,7 +185,7 @@
     mutable std::mutex fd_mutex_;
 
     bool WriteValueToFile(const std::string& value, ResourceCacheType cache_type, uid_t uid,
-                          int pid, bool logfailures) const;
+                          pid_t pid, bool logfailures) const;
     CacheUseResult UseCachedFd(ResourceCacheType cache_type, const std::string& value) const;
 };