62a1ddeaee
Fixes the reported GPU time regression when rendering platform views. The problem was that we delayed the tracing of the end of the frame until the CATransaction, which artificially stretches out GPU frame time. Instead add a new method SurfaceMTL::PreparePResent which performs the final blit and tracing, call this in the encode callback. Fixes: https://flutter-flutter-perf.skia.org/e/?queries=sub_result%3Daverage_gpu_frame_time%26test%3Dplatform_views_scroll_perf_ios__timeline_summary&selected=commit%3D41853%26name%3D%252Carch%253Dintel%252Cbranch%253Dmaster%252Cconfig%253Ddefault%252Cdevice_type%253DiPhone_11%252Cdevice_version%253Dnone%252Chost_type%253Dmac%252Csub_result%253Daverage_gpu_frame_time%252Ctest%253Dplatform_views_scroll_perf_ios__timeline_summary%252C Test: benchmarks.