Move get_time() helper to core

We'll need a better strategy for generating timestamps without input events
or pageflips.  At least we'll need to ensure everybody is using the same
underlying time source.

wayland/wayland-server.c

@@ -32,6 +32,7 @@
 #include <sys/un.h>
 #include <dlfcn.h>
 #include <assert.h>
+#include <sys/time.h>
 #include <ffi.h>
 
 #include "wayland-server.h"
@@ -484,6 +485,16 @@ wl_display_destroy(struct wl_display *display)
 	free(display);
 }
 
+WL_EXPORT uint32_t
+wl_display_get_time(struct wl_display *display)
+{
+	struct timeval tv;
+
+	gettimeofday(&tv, NULL);
+
+	return tv.tv_sec * 1000 + tv.tv_usec / 1000;
+}
+
 WL_EXPORT void
 wl_display_add_object(struct wl_display *display, struct wl_object *object)
 {

wayland/wayland-server.h

@@ -177,6 +177,9 @@ wl_display_set_compositor(struct wl_display *display,
 			  struct wl_compositor *compositor,
 			  const struct wl_compositor_interface *implementation);
 
+uint32_t
+wl_display_get_time(struct wl_display *display);
+
 void
 wl_display_post_frame(struct wl_display *display, uint32_t msecs);