Make ui_chromeos_resources IDRs accessible via chrome://theme/<IDR>.

chrome/browser/resources_util_unittest.cc

Index: chrome/browser/resources_util_unittest.cc
diff --git a/chrome/browser/resources_util_unittest.cc b/chrome/browser/resources_util_unittest.cc
index 763755943e3f15f21314fd032e451aabc53ac035..ec52eefd6fc95205f5c3336d26d69236d13e5805 100644
--- a/chrome/browser/resources_util_unittest.cc
+++ b/chrome/browser/resources_util_unittest.cc
@@ -8,6 +8,10 @@
 #include "grit/ui_resources.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
+#if defined(OS_CHROMEOS)
+#include "grit/ui_chromeos_resources.h"
+#endif
+
 TEST(ResourcesUtil, SpotCheckIds) {
   const struct {
     const char* name;
@@ -19,6 +23,10 @@ TEST(ResourcesUtil, SpotCheckIds) {
     // IDRs from ui/resources/ui_resources.grd should be valid.
     {"IDR_CHECKMARK", IDR_CHECKMARK},
     {"IDR_THROBBER", IDR_THROBBER},
+#if defined(OS_CHROMEOS)
+    // Check IDRs from ui/chromeos/resources/ui_chromeos_resources.grd.
+    {"IDR_LOGIN_DEFAULT_USER", IDR_LOGIN_DEFAULT_USER},
+#endif
     // Unknown names should be invalid and return -1.
     {"foobar", -1},
     {"backstar", -1},