types: Move SdEventDuration out of internal

Change-Id: I71f9ca6736268edc9920d4489d0e15b4f56b410d
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/src/sdeventplus/clock.hpp b/src/sdeventplus/clock.hpp
index 8af9143..7851a98 100644
--- a/src/sdeventplus/clock.hpp
+++ b/src/sdeventplus/clock.hpp
@@ -5,6 +5,7 @@
 #include <ctime>
 #include <sdeventplus/event.hpp>
 #include <sdeventplus/internal/utils.hpp>
+#include <sdeventplus/types.hpp>
 #include <type_traits>
 
 namespace sdeventplus
diff --git a/src/sdeventplus/internal/utils.hpp b/src/sdeventplus/internal/utils.hpp
index ec572e4..9b18dee 100644
--- a/src/sdeventplus/internal/utils.hpp
+++ b/src/sdeventplus/internal/utils.hpp
@@ -1,18 +1,11 @@
 #pragma once
 
-#include <chrono>
-#include <cstdint>
 #include <sdeventplus/exception.hpp>
 #include <stdplus/util/cexec.hpp>
 #include <utility>
 
 namespace sdeventplus
 {
-
-// Defined by systemd taking uint64_t usec params
-using SdEventDuration =
-    std::chrono::duration<uint64_t, std::chrono::microseconds::period>;
-
 namespace internal
 {
 
diff --git a/src/sdeventplus/types.hpp b/src/sdeventplus/types.hpp
index 4508f3e..2654f2e 100644
--- a/src/sdeventplus/types.hpp
+++ b/src/sdeventplus/types.hpp
@@ -1,7 +1,14 @@
 #pragma once
+#include <chrono>
+#include <cstdint>
 
 namespace sdeventplus
 {
+
+// Defined by systemd taking uint64_t usec params
+using SdEventDuration =
+    std::chrono::duration<uint64_t, std::chrono::microseconds::period>;
+
 namespace internal
 {