Function fake_frame

native/shared/src/profiler.rs:370–375

Drive the profiler through `frame_end` purely on the CPU side (gpu_enabled stays false). Each "frame" pushes a single sample with the given cpu_us so the histogram totals are known.

(p: &mut Profiler, cpu_us: f64)

    /// sample with the given cpu_us so the histogram totals are
    /// known.
    fn fake_frame(p: &mut Profiler, cpu_us: f64) {
        p.frame.push(FrameSample { label: "fake", cpu_us, gpu_us: None });
        // Skip the gpu readback path (no device available) and go
        // straight to the CPU-only histogram + drain path.
        p.frame_end_cpu();
    }

    #[test]
    fn frame_history_empty_before_any_frames() {