From 501354c207cee1b36320783f5664134c47beaa06 Mon Sep 17 00:00:00 2001
From: stuartmorgan <stuartmorgan@google.com>
Date: Wed, 8 May 2019 23:20:32 -0400
Subject: [PATCH] Fix TimePoint on Windows (flutter/engine#8910)

Addresses overflow issues with timer multiplication by using std::chrono
instead of QueryPerformanceCounter. The Windows implementation of
std::chrono uses QPC, so this should have no impact on performance or
clock resolution.

Fixes #32121
---
 engine/src/flutter/fml/time/time_point.cc | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/engine/src/flutter/fml/time/time_point.cc b/engine/src/flutter/fml/time/time_point.cc
index f0a912e92f..695dca8927 100644
--- a/engine/src/flutter/fml/time/time_point.cc
+++ b/engine/src/flutter/fml/time/time_point.cc
@@ -12,7 +12,7 @@
 #elif defined(OS_FUCHSIA)
 #include <zircon/syscalls.h>
 #elif defined(OS_WIN)
-#include <windows.h>
+#include <chrono>
 #else
 #include <time.h>
 #endif  // defined(OS_MACOSX) || defined(OS_IOS)
@@ -53,11 +53,11 @@ TimePoint TimePoint::Now() {
 #elif defined(OS_WIN)
 
 TimePoint TimePoint::Now() {
-  uint64_t freq = 0;
-  uint64_t count = 0;
-  QueryPerformanceFrequency((LARGE_INTEGER*)&freq);
-  QueryPerformanceCounter((LARGE_INTEGER*)&count);
-  return TimePoint((count * 1000000000) / freq);
+  // The base time is arbitrary; use the clock epoch for convenience.
+  const auto elapsed_time = std::chrono::steady_clock::now().time_since_epoch();
+  return TimePoint(
+      std::chrono::duration_cast<std::chrono::nanoseconds>(elapsed_time)
+          .count());
 }
 
 #else