clutter/frame: Carry target presentation time

This will be used, when available, to both check whether frames missed a
vsync cycle, or to calculate when page flips should be queued.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2795>

clutter/clutter/clutter-frame-clock.c

@@ -733,6 +733,8 @@ clutter_frame_clock_dispatch (ClutterFrameClock *frame_clock,
 
   frame = g_new0 (ClutterFrame, 1);
   frame->frame_count = frame_count;
+  frame->has_target_presentation_time = frame_clock->is_next_presentation_time_valid;
+  frame->target_presentation_time_us = frame_clock->next_presentation_time_us;
 
   COGL_TRACE_BEGIN (ClutterFrameClockEvents, "Frame Clock (before frame)");
   if (iface->before_frame)

clutter/clutter/clutter-frame-private.h

@@ -24,6 +24,9 @@ struct _ClutterFrame
 {
   int64_t frame_count;
 
+  gboolean has_target_presentation_time;
+  int64_t target_presentation_time_us;
+
   gboolean has_result;
   ClutterFrameResult result;
 };

clutter/clutter/clutter-frame.c

@@ -23,6 +23,21 @@ clutter_frame_get_count (ClutterFrame *frame)
   return frame->frame_count;
 }
 
+gboolean
+clutter_frame_get_target_presentation_time (ClutterFrame *frame,
+                                            int64_t      *target_presentation_time_us)
+{
+  if (frame->has_target_presentation_time)
+    {
+      *target_presentation_time_us = frame->target_presentation_time_us;
+      return TRUE;
+    }
+  else
+    {
+      return FALSE;
+    }
+}
+
 ClutterFrameResult
 clutter_frame_get_result (ClutterFrame *frame)
 {

clutter/clutter/clutter-frame.h

@@ -29,6 +29,10 @@ typedef struct _ClutterFrame ClutterFrame;
 CLUTTER_EXPORT
 int64_t clutter_frame_get_count (ClutterFrame *frame);
 
+CLUTTER_EXPORT
+gboolean clutter_frame_get_target_presentation_time (ClutterFrame *frame,
+                                                     int64_t      *target_presentation_time_us);
+
 CLUTTER_EXPORT
 void clutter_frame_set_result (ClutterFrame       *frame,
                                ClutterFrameResult  result);