mustash: Connect ash system tray "show settings" items to chrome over mojo

ash/common/system/chromeos/network/network_state_list_detailed_view.cc

Index: ash/common/system/chromeos/network/network_state_list_detailed_view.cc
diff --git a/ash/common/system/chromeos/network/network_state_list_detailed_view.cc b/ash/common/system/chromeos/network/network_state_list_detailed_view.cc
index bb10f282ebf7f6907aa735e6e4729fd4c72a2938..d9d9d89e645e7aa7325cb0fec516561985d95149 100644
--- a/ash/common/system/chromeos/network/network_state_list_detailed_view.cc
+++ b/ash/common/system/chromeos/network/network_state_list_detailed_view.cc
@@ -398,7 +398,7 @@ void NetworkStateListDetailedView::HandleButtonPressed(views::Button* sender,
     ShowSettings();
     close_bubble = true;
   } else if (sender == proxy_settings_) {
-    delegate->ChangeProxySettings();
+    delegate->ShowProxySettings();
     close_bubble = true;
   } else if (sender == other_mobile_) {
     delegate->ShowOtherNetworkDialog(shill::kTypeCellular);