Refactor OS_LINUX preprocessor directive for LaCrOS effort.

Currently, ChromeOS defines the OS_LINUX directive as well as
OS_CHROMEOS.  We're working to separate these two, so we're
making the fact that OS_LINUX == OS_LINUX || OS_CHROMEOS
explicit.

Bug: 1110266
Change-Id: I5aedb1ceaad41242f4a51d450704027dcb0c046e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2352022
Commit-Queue: Sean McAllister <smcallis@google.com>
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Reviewed-by: Peng Huang <penghuang@chromium.org>
Reviewed-by: dsinclair <dsinclair@chromium.org>
Reviewed-by: Reilly Grant <reillyg@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Reviewed-by: Raymes Khoury <raymes@chromium.org>
Reviewed-by: Primiano Tucci <primiano@chromium.org>
Cr-Commit-Position: refs/heads/master@{#799843}
GitOrigin-RevId: b9ad65a619005928f421487199b34a979c63e60f
diff --git a/src/config.h b/src/config.h
index 62c1276..9c1cec1 100644
--- a/src/config.h
+++ b/src/config.h
@@ -10,7 +10,7 @@
 #include "third_party/tcmalloc/chromium/src/config_win.h"
 #elif defined(OS_ANDROID)
 #include "third_party/tcmalloc/chromium/src/config_android.h"
-#elif defined(OS_LINUX)
+#elif defined(OS_LINUX) || defined(OS_CHROMEOS)
 #include "third_party/tcmalloc/chromium/src/config_linux.h"
 #elif defined(OS_FREEBSD)
 #include "third_party/tcmalloc/chromium/src/config_freebsd.h"