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.

This is changes for /chrome/test/nacl

This CL was uploaded by git cl split.

R=mseaborn@chromium.org

Bug: 1110266
Change-Id: Id5873d48ebdcbe98564b6b5c47015f4ad5f8985e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2371284
Auto-Submit: Sean McAllister <smcallis@google.com>
Reviewed-by: Mark Seaborn <mseaborn@chromium.org>
Commit-Queue: Mark Seaborn <mseaborn@chromium.org>
Cr-Commit-Position: refs/heads/master@{#801116}

chrome/test/nacl/nacl_browsertest_util.h

@@ -172,8 +172,7 @@ class NaClBrowserTestGLibcExtension : public NaClBrowserTestGLibc {
 // https://code.google.com/p/chromium/issues/detail?id=177555
 #if (defined(OS_WIN) && !defined(NDEBUG))
 #  define MAYBE_PNACL(test_name) DISABLED_##test_name
-#elif defined(ADDRESS_SANITIZER) && \
-  (defined(OS_LINUX) || defined(OS_CHROMEOS))
+#elif (defined(OS_LINUX) || defined(OS_CHROMEOS)) && defined(ADDRESS_SANITIZER)
 // NaClBrowserTestPnacl tests are very flaky on ASan, see crbug.com/1003259.
 #  define MAYBE_PNACL(test_name) DISABLED_##test_name
 #else