From 89e4666ee652e542d08af5684ad711f2e3265f71 Mon Sep 17 00:00:00 2001
From: Matt Oakes <hello@mattoakes.net>
Date: Tue, 8 Sep 2020 17:46:31 +0100
Subject: [PATCH] Revert the changes to idle timers made in #26114

This was causing issues with the window.requestIdleCallback timers as the timer code was expecting this "timestamp" property to be a unix timestamp in seconds which was causing the calculations to be done incorrectly and for the callbacks to never be called.

Fixes #28602
---
 React/CoreModules/RCTTiming.mm | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/React/CoreModules/RCTTiming.mm b/React/CoreModules/RCTTiming.mm
index 13d0d57296bbba..6065006b8eb281 100644
--- a/React/CoreModules/RCTTiming.mm
+++ b/React/CoreModules/RCTTiming.mm
@@ -256,9 +256,9 @@ - (void)didUpdateFrame:(RCTFrameUpdate *)update
   }
 
   if (_sendIdleEvents) {
-    NSTimeInterval currentTimestamp = [[NSDate date] timeIntervalSince1970];
-    NSTimeInterval frameElapsed = currentTimestamp - update.timestamp;
+    NSTimeInterval frameElapsed = (CACurrentMediaTime() - update.timestamp);
     if (kFrameDuration - frameElapsed >= kIdleCallbackFrameDeadline) {
+      NSTimeInterval currentTimestamp = [[NSDate date] timeIntervalSince1970];
       NSNumber *absoluteFrameStartMS = @((currentTimestamp - frameElapsed) * 1000);
       if (_bridge) {
         [_bridge enqueueJSCall:@"JSTimers" method:@"callIdleCallbacks" args:@[ absoluteFrameStartMS ] completion:NULL];