Replace CHROMEOS macro with OS_CHROMEOS

CHROMEOS macro is defined in third_party/webrtc.
This CL replaces it with more appropriate macro.

Bug: None
Change-Id: I7c5c5928424c026b1fb679814617c1134c0d5537
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2022584Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Commit-Queue: Hiroki Sato <hirokisato@chromium.org>
Cr-Commit-Position: refs/heads/master@{#735658}

chrome/browser/extensions/chrome_extension_function_unittest.cc

@@ -55,7 +55,7 @@ class ValidationFunction : public ExtensionFunction {
 
 using ChromeExtensionFunctionUnitTest = ExtensionServiceTestBase;
 
-#if defined(OS_WIN) || defined(CHROMEOS)
+#if defined(OS_WIN) || defined(OS_CHROMEOS)
 #define MAYBE_SimpleFunctionTest DISABLED_SimpleFunctionTest
 #else
 #define MAYBE_SimpleFunctionTest SimpleFunctionTest

chrome/browser/extensions/process_manager_browsertest.cc

@@ -53,7 +53,7 @@
 #include "net/dns/mock_host_resolver.h"
 #include "net/test/embedded_test_server/embedded_test_server.h"
 
-#if defined(CHROMEOS)
+#if defined(OS_CHROMEOS)
 #include "chrome/browser/chromeos/profiles/profile_helper.h"
 #include "chromeos/constants/chromeos_switches.h"
 #endif