Wait on the monotonic clock to guard against changes to the system clock.

runtime/vm/globals.h

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_GLOBALS_H_
 #define VM_GLOBALS_H_
 
 // __STDC_FORMAT_MACROS has to be defined to enable platform independent printf.
 #ifndef __STDC_FORMAT_MACROS
 #define __STDC_FORMAT_MACROS
@@ skipping 140 matching lines @@
 // Bit sizes.
 const int kBitsPerByte = 8;
 const int kBitsPerByteLog2 = 3;
 const int kBitsPerWord = kWordSize * kBitsPerByte;
 
 // System-wide named constants.
 const int KB = 1024;
 const int MB = KB * KB;
 const int GB = KB * KB * KB;
 
+// Time constants.
+const int kMillisecondsPerSecond = 1000;
+const int kMicrosecondsPerMillisecond = 1000;
+const int kMicrosecondsPerSecond = (kMicrosecondsPerMillisecond *
+                                    kMillisecondsPerSecond);
+const int kNanosecondsPerMicrosecond = 1000;
+const int kNanosecondsPerMillisecond = (kNanosecondsPerMicrosecond *
+                                        kMicrosecondsPerMillisecond);
+const int kNanosecondsPerSecond = (kNanosecondsPerMicrosecond *
+                                   kMicrosecondsPerSecond);
+
 // A macro to disallow the copy constructor and operator= functions.
 // This should be used in the private: declarations for a class.
 #define DISALLOW_COPY_AND_ASSIGN(TypeName)                                     \
 private:                                                                       \
   TypeName(const TypeName&);                                                   \
   void operator=(const TypeName&)
 
 
 // A macro to disallow all the implicit constructors, namely the default
 // constructor, copy constructor and operator= functions. This should be
@@ skipping 156 matching lines @@
 // contants are 16 byte aligned.
 #if defined(TARGET_OS_WINDOWS)
 #define ALIGN16 __declspec(align(16))
 #else
 #define ALIGN16 __attribute__((aligned(16)))
 #endif
 
 }  // namespace dart
 
 #endif  // VM_GLOBALS_H_