installd: add missing <functional> for std::function.

Bug: b/175635923
Test: treehugger
Change-Id: I2541263d27b5bced25667baaf814bff0e65e4604
diff --git a/cmds/installd/CrateManager.cpp b/cmds/installd/CrateManager.cpp
index b17cba1..fd1df35 100644
--- a/cmds/installd/CrateManager.cpp
+++ b/cmds/installd/CrateManager.cpp
@@ -29,9 +29,10 @@
 #include <sys/xattr.h>
 #include <unistd.h>
 
-#include <fstream>
-#include <string>
 #include <utils.h>
+#include <fstream>
+#include <functional>
+#include <string>
 
 #include "utils.h"
 
diff --git a/cmds/installd/CrateManager.h b/cmds/installd/CrateManager.h
index 1f30b5d..d9b590f 100644
--- a/cmds/installd/CrateManager.h
+++ b/cmds/installd/CrateManager.h
@@ -25,6 +25,7 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 
+#include <functional>
 #include <optional>
 #include <string>
 #include <vector>
diff --git a/cmds/installd/utils.h b/cmds/installd/utils.h
index ecea1d2..c43fdbd 100644
--- a/cmds/installd/utils.h
+++ b/cmds/installd/utils.h
@@ -18,6 +18,7 @@
 #ifndef UTILS_H_
 #define UTILS_H_
 
+#include <functional>
 #include <string>
 #include <vector>