Guest mode causes certain settings to be hidden.

chrome/browser/ui/webui/options/startup_pages_handler.cc

Index: chrome/browser/ui/webui/options/startup_pages_handler.cc
diff --git a/chrome/browser/ui/webui/options/startup_pages_handler.cc b/chrome/browser/ui/webui/options/startup_pages_handler.cc
index ca729b163b5f1afc2be8b96981cf0849a4194025..56f94813efd003cc8f5a0b2d871d0b63c5fa2473 100644
--- a/chrome/browser/ui/webui/options/startup_pages_handler.cc
+++ b/chrome/browser/ui/webui/options/startup_pages_handler.cc
@@ -48,6 +48,11 @@ void StartupPagesHandler::GetLocalizedValues(
 }
 
 void StartupPagesHandler::RegisterMessages() {
+  // Guest profiles should never have been displayed the option to set
+  // these values.

[Evan Stade, 2014/08/19 17:49:13]

nit: I don't think this comment is necessary

[Mike Lerman, 2014/08/19 20:34:12]

Acknowledged.

+  if (Profile::FromWebUI(web_ui())->IsOffTheRecord())

[Evan Stade, 2014/08/19 17:49:13]

would it be possible to not even create the StartupPagesHandler in the OTR case?

[Mike Lerman, 2014/08/19 20:34:12]

Done, removed this call here and added a check in options_ui.

+    return;
+
   web_ui()->RegisterMessageCallback("removeStartupPages",
       base::Bind(&StartupPagesHandler::RemoveStartupPages,
                  base::Unretained(this)));