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 /content/browser/site_per_process_browsertest.cc

This CL was uploaded by git cl split.

R=kenrb@chromium.org

Bug: 1110266
Change-Id: Ic527921e0dfa915b92e89ede01f3b8c507d68d95
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2371290Reviewed-by: Ken Buchanan <kenrb@chromium.org>
Commit-Queue: Ken Buchanan <kenrb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#801183}

content/browser/site_per_process_browsertest.cc

@@ -3989,7 +3989,7 @@ IN_PROC_BROWSER_TEST_P(SitePerProcessBrowserTest, ProxyCreationSkipsSubtree) {
 // TODO(bokan): Pretty soon most/all platforms will use overlay scrollbars. This
 // test should find a better way to check for scrollability. crbug.com/662196.
 // Flaky on Linux. crbug.com/790929.
-#if defined(OS_ANDROID) || defined(OS_LINUX)
+#if defined(OS_ANDROID) || defined(OS_LINUX) || defined(OS_CHROMEOS)
 #define MAYBE_FrameOwnerPropertiesPropagationScrolling \
   DISABLED_FrameOwnerPropertiesPropagationScrolling
 #else
@@ -13731,7 +13731,8 @@ class SitePerProcessBrowserTestWithSadFrameTabReload
 // shown. See https://crbug.com/841572.
 // crbug.com/1010119, fails on Win. crbug.com/1015971, fails on Linux.
 // crbug.com/1049885, fails on Android.
-#if defined(OS_WIN) || defined(OS_LINUX) || defined(OS_ANDROID)
+#if defined(OS_WIN) || defined(OS_LINUX) || defined(OS_CHROMEOS) || \
+    defined(OS_ANDROID)
 #define MAYBE_ReloadHiddenTabWithCrashedSubframe \
   DISABLED_ReloadHiddenTabWithCrashedSubframe
 #else