Worker spinlocks using 'get_now()' for audio worklet compatibility

Author: cwoffenden

system/lib/wasm_worker/library_wasm_worker.c

@@ -105,15 +105,19 @@ void emscripten_lock_waitinf_acquire(emscripten_lock_t *lock) {
 }
 
 bool emscripten_lock_busyspin_wait_acquire(emscripten_lock_t *lock, double maxWaitMilliseconds) {
+  // Note: using emscripten_get_now() over emscripten_performance_now() to allow
+  // compatibility with Audio Worklets (but for workers this will defer to the
+  // performance call with its higher granularity). We keep the non-busy locks
+  // using the performance version since they have waits, incompatible with AWs.
   emscripten_lock_t val = emscripten_atomic_cas_u32((void*)lock, 0, 1);
   if (!val) return true;
 
-  double t = emscripten_performance_now();
+  double t = emscripten_get_now();
   double waitEnd = t + maxWaitMilliseconds;
   while (t < waitEnd) {
     val = emscripten_atomic_cas_u32((void*)lock, 0, 1);
     if (!val) return true;
-    t = emscripten_performance_now();
+    t = emscripten_get_now();
   }
   return false;
 }