Append --iframe-security to renderer process.

browser/atom_browser_client.h

@@ -25,6 +25,8 @@ class AtomBrowserClient : public brightray::BrowserClient {
       content::SiteInstance* site_instance,
       const GURL& current_url,
       const GURL& new_url) OVERRIDE;
+  virtual void AppendExtraCommandLineSwitches(CommandLine* command_line,
+                                              int child_process_id) OVERRIDE;
 
  private:
   virtual brightray::BrowserMainParts* OverrideCreateBrowserMainParts(