[fuchsia] Remove SceneDisplayLag event on Fuchsia (#18515)

See: https://github.com/flutter/flutter/issues/56598

shell/common/rasterizer.cc

@@ -257,7 +257,9 @@ RasterStatus Rasterizer::DoDraw(
   }
 
   FrameTiming timing;
+#if !defined(OS_FUCHSIA)
   const fml::TimePoint frame_target_time = layer_tree->target_time();
+#endif
   timing.Set(FrameTiming::kBuildStart, layer_tree->build_start());
   timing.Set(FrameTiming::kBuildFinish, layer_tree->build_finish());
   timing.Set(FrameTiming::kRasterStart, fml::TimePoint::Now());
@@ -287,6 +289,9 @@ RasterStatus Rasterizer::DoDraw(
   timing.Set(FrameTiming::kRasterFinish, raster_finish_time);
   delegate_.OnFrameRasterized(timing);
 
+// SceneDisplayLag events are disabled on Fuchsia.
+// see: https://github.com/flutter/flutter/issues/56598
+#if !defined(OS_FUCHSIA)
   if (raster_finish_time > frame_target_time) {
     fml::TimePoint latest_frame_target_time =
         delegate_.GetLatestFrameTargetTime();
@@ -312,6 +317,7 @@ RasterStatus Rasterizer::DoDraw(
         vsync_transitions_missed      // arg_val_3
     );
   }
+#endif
 
   // Pipeline pressure is applied from a couple of places:
   // rasterizer: When there are more items as of the time of Consume.