win: clock implementation

util/misc/clock.h

 // Copyright 2014 The Crashpad Authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
@@ skipping 19 matching lines @@
 //! series of increasing values.
 //!
 //! \return The value of the system’s monotonic clock, in nanoseconds.
 uint64_t ClockMonotonicNanoseconds();
 
 //! \brief Sleeps for the specified duration.
 //!
 //! \param[in] nanoseconds The number of nanoseconds to sleep. The actual sleep
 //!     may be slightly longer due to latencies and timer resolution.
 //!
-//! This function is resilient against the underlying `nanosleep()` system call
-//! being interrupted by a signal.
+//! On POSIX, this function is resilient against the underlying `nanosleep()`
+//! system call being interrupted by a signal. On Windows, the global system
+//! timer resolution is not modified with `timeBeginPeriod()`, so the time
+//! slept will have a resolution of approximately 16ms by default.
 void SleepNanoseconds(uint64_t nanoseconds);
 
 }  // namespace crashpad
 
 #endif  // CRASHPAD_UTIL_MISC_CLOCK_H_