Use LockFile/UnlockFile for Settings to port to Windows

util/misc/uuid.h

Index: util/misc/uuid.h
diff --git a/util/misc/uuid.h b/util/misc/uuid.h
index 29b36bc09b8c8c26ded6dd6e63effa7d23b5fb87..f7e1ee804035b648ba8deb745ed285e5e6cf2bba 100644
--- a/util/misc/uuid.h
+++ b/util/misc/uuid.h
@@ -67,6 +67,13 @@ struct UUID {
   //!     parsed, with the object state untouched.
   bool InitializeFromString(const base::StringPiece& string);
 
+  //! \brief Initializes the %UUID using a standard system facility to generate
+  //!     the value.
+  //!
+  //! \return `true` if the %UUID was initialized correctly, `false` otherwise
+  //!     with a message logged.
+  bool InitializeWithNew();
+
 #if defined(OS_WIN) || DOXYGEN
   //! \brief Initializes the %UUID from a system `UUID` or `GUID` structure.
   //!