[dart:io] Adds Platform.operatingSystemVersion

runtime/bin/platform.h

 // Copyright (c) 2012, 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 RUNTIME_BIN_PLATFORM_H_
 #define RUNTIME_BIN_PLATFORM_H_
 
 #include "bin/builtin.h"
 #include "platform/globals.h"
 
 namespace dart {
 namespace bin {
 
 class Platform {
  public:
   // Perform platform specific initialization.
   static bool Initialize();
 
   // Returns the number of processors on the machine.
   static int NumberOfProcessors();
 
   // Returns a string representing the operating system ("linux",
   // "macos", "windows", or "android"). The returned string should not be
   // deallocated by the caller.
   static const char* OperatingSystem();
 
+  // Returns a string representing the version of the operating system. The
+  // format of the string is determined by the platform. The returned string
+  // should not be deallocated by the caller.
+  static const char* OperatingSystemVersion();
+
   // Returns the architecture name of the processor the VM is running on
   // (ia32, x64, arm, or arm64).
   static const char* HostArchitecture() {
 #if defined(HOST_ARCH_ARM)
     return "arm";
 #elif defined(HOST_ARCH_ARM64)
     return "arm64";
 #elif defined(HOST_ARCH_IA32)
     return "ia32";
 #elif defined(HOST_ARCH_X64)
@@ skipping 58 matching lines @@
   static char** argv_;  // VM flags are argv_[1 ... script_index_ - 1]
 
   DISALLOW_ALLOCATION();
   DISALLOW_IMPLICIT_CONSTRUCTORS(Platform);
 };
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // RUNTIME_BIN_PLATFORM_H_