[dart:io] Adds Platform.operatingSystemVersion

runtime/bin/platform.cc

Index: runtime/bin/platform.cc
diff --git a/runtime/bin/platform.cc b/runtime/bin/platform.cc
index 88a52a26daa444128882d554237641f1add8845a..20c7ff01108782f8c60802b81aaa9bec4ed52253 100644
--- a/runtime/bin/platform.cc
+++ b/runtime/bin/platform.cc
@@ -19,6 +19,15 @@ void FUNCTION_NAME(Platform_OperatingSystem)(Dart_NativeArguments args) {
   Dart_SetReturnValue(args, DartUtils::NewString(Platform::OperatingSystem()));
 }
 
+void FUNCTION_NAME(Platform_OperatingSystemVersion)(Dart_NativeArguments args) {
+  const char* version = Platform::OperatingSystemVersion();
+  if (version == NULL) {
+    Dart_SetReturnValue(args, DartUtils::NewDartOSError());
+  } else {
+    Dart_SetReturnValue(args, DartUtils::NewString(version));
+  }
+}
+
 void FUNCTION_NAME(Platform_PathSeparator)(Dart_NativeArguments args) {
   Dart_SetReturnValue(args, DartUtils::NewString(File::PathSeparator()));
 }