Make ChromeOSVersionInfo singleton leaky to avoid startup thread restriction DCHECK

It doesn't do any interesting work on shutdown. The check was added today with
https://codereview.chromium.org/1904273002/

This is needed to run a target_os="chromeos" build on Linux.

BUG=none
TEST=none

Review-Url: https://codereview.chromium.org/2167493004
Cr-Commit-Position: refs/heads/master@{#406395}


CrOS-Libchrome-Original-Commit: 5aa2d8c58b4dbb74437652c32dcdfec5a323db44
diff --git a/base/sys_info_chromeos.cc b/base/sys_info_chromeos.cc
index 3794ed9..e4d671f 100644
--- a/base/sys_info_chromeos.cc
+++ b/base/sys_info_chromeos.cc
@@ -163,7 +163,7 @@
   bool is_running_on_chromeos_;
 };
 
-static LazyInstance<ChromeOSVersionInfo>
+static LazyInstance<ChromeOSVersionInfo>::Leaky
     g_chrome_os_version_info = LAZY_INSTANCE_INITIALIZER;
 
 ChromeOSVersionInfo& GetChromeOSVersionInfo() {