Only refer to _WIN resources on Windows.

chrome/browser/managed_mode/managed_user_theme.cc

Index: chrome/browser/managed_mode/managed_user_theme.cc
===================================================================
--- chrome/browser/managed_mode/managed_user_theme.cc	(revision 243958)
+++ chrome/browser/managed_mode/managed_user_theme.cc	(working copy)
@@ -21,14 +21,20 @@
 int MapToManagedUserResourceIds(int id) {
   switch (id) {
     case IDR_THEME_FRAME:
+#if defined(OS_WIN)
     case IDR_THEME_FRAME_WIN:
+#endif
       return IDR_MANAGED_USER_THEME_FRAME;
     case IDR_THEME_FRAME_INACTIVE:
+#if defined(OS_WIN)
     case IDR_THEME_FRAME_INACTIVE_WIN:
+#endif
       return IDR_MANAGED_USER_THEME_FRAME_INACTIVE;
     case IDR_THEME_TAB_BACKGROUND:
     case IDR_THEME_TAB_BACKGROUND_V:
+#if defined(OS_WIN)
     case IDR_THEME_TAB_BACKGROUND_WIN:
+#endif
       return IDR_MANAGED_USER_THEME_TAB_BACKGROUND;
   }
   return id;