Bug 1167294 - follow-up, use #ifdef instead of AppConstants. r=me

--HG--
extra : rebase_source : b6b3ab72ba4bdb65b06d89425ab16a3525add9cd

browser/components/nsBrowserGlue.js

@@ -2626,16 +2626,16 @@ let DefaultBrowserCheck = {
 
   setAsDefault: function() {
     let claimAllTypes = true;
-    if (AppConstants.platform == "win") {
-      try {
-        // In Windows 8+, the UI for selecting default protocol is much
-        // nicer than the UI for setting file type associations. So we
-        // only show the protocol association screen on Windows 8+.
-        // Windows 8 is version 6.2.
-        let version = Services.sysinfo.getProperty("version");
-        claimAllTypes = (parseFloat(version) < 6.2);
-      } catch (ex) { }
-    }
+#ifdef XP_WIN
+    try {
+      // In Windows 8+, the UI for selecting default protocol is much
+      // nicer than the UI for setting file type associations. So we
+      // only show the protocol association screen on Windows 8+.
+      // Windows 8 is version 6.2.
+      let version = Services.sysinfo.getProperty("version");
+      claimAllTypes = (parseFloat(version) < 6.2);
+    } catch (ex) { }
+#endif
     try {
       ShellService.setDefaultBrowser(claimAllTypes, false);
     } catch (ex) {