fix: performance.timeOrigin (#26787)

`performance.timeOrigin` was being set from when JS started executing,
but `op_now` measures from an `std::time::Instant` stored in `OpState`,
which is created at a completely different time. This caused
`performance.timeOrigin` to be very incorrect. This PR corrects the
origin and also cleans up some of the timer code.

Compared to `Date.now()`, `performance`'s time origin is now
consistently within 5us (0.005ms) of system time.


![image](https://github.com/user-attachments/assets/0a7be04a-4f6d-4816-bd25-38a2e6136926)

1 files changed, 2 insertions, 2 deletions

diff --git a/cli/ops/bench.rs b/cli/ops/bench.rs
index 79a7ddef0..1f4a4bd9b 100644
--- a/cli/ops/bench.rs
+++ b/cli/ops/bench.rs
@@ -2,7 +2,6 @@
 
 use std::sync::atomic::AtomicUsize;
 use std::sync::atomic::Ordering;
-use std::time;
 
 use deno_core::error::generic_error;
 use deno_core::error::type_error;
@@ -13,6 +12,7 @@ use deno_core::ModuleSpecifier;
 use deno_core::OpState;
 use deno_runtime::deno_permissions::ChildPermissionsArg;
 use deno_runtime::deno_permissions::PermissionsContainer;
+use deno_runtime::deno_web::StartTime;
 use tokio::sync::mpsc::UnboundedSender;
 use uuid::Uuid;
 
@@ -148,7 +148,7 @@ fn op_dispatch_bench_event(state: &mut OpState, #[serde] event: BenchEvent) {
 #[op2(fast)]
 #[number]
 fn op_bench_now(state: &mut OpState) -> Result<u64, std::num::TryFromIntError> {
-  let ns = state.borrow::<time::Instant>().elapsed().as_nanos();
+  let ns = state.borrow::<StartTime>().elapsed().as_nanos();
   let ns_u64 = u64::try_from(ns)?;
   Ok(ns_u64)
 }