Stop the OverviewButton from appearing on the Add-User screen

ash/system/overview/overview_button_tray.cc

Index: ash/system/overview/overview_button_tray.cc
diff --git a/ash/system/overview/overview_button_tray.cc b/ash/system/overview/overview_button_tray.cc
index edd5d67dd0697dd2598133cc5289d83e7511831f..3385dc8884f932a1d2e8db588a6fd5dc6f829fba 100644
--- a/ash/system/overview/overview_button_tray.cc
+++ b/ash/system/overview/overview_button_tray.cc
@@ -4,6 +4,7 @@
 
 #include "ash/system/overview/overview_button_tray.h"
 
+#include "ash/session/session_state_delegate.h"
 #include "ash/shelf/shelf_types.h"
 #include "ash/shell.h"
 #include "ash/system/tray/system_tray_delegate.h"
@@ -42,14 +43,21 @@ OverviewButtonTray::OverviewButtonTray(StatusAreaWidget* status_area_widget)
   tray_container()->AddChildView(icon_);
 
   Shell::GetInstance()->AddShellObserver(this);
+  Shell::GetInstance()->session_state_delegate()->AddSessionStateObserver(this);
 }
 
 OverviewButtonTray::~OverviewButtonTray() {
   Shell::GetInstance()->RemoveShellObserver(this);
+  Shell::GetInstance()->session_state_delegate()->RemoveSessionStateObserver(
+      this);
 }
 
 void OverviewButtonTray::UpdateAfterLoginStatusChange(
     user::LoginStatus status) {
+  if (status == user::LOGGED_IN_KIOSK_APP) {
+    SetVisible(false);

[flackr, 2015/06/01 17:05:32]

What guarantee is there that the visibility won't be later updated not taking
into account this state? Seems like it would be better to save the loginstatus
if you can't query for LOGGED_IN_KIOSK_APP.

[jonross, 2015/06/01 17:20:37]

Good point.

Done.

+    return;
+  }
   UpdateIconVisibility();
 }
 
@@ -62,6 +70,11 @@ bool OverviewButtonTray::PerformAction(const ui::Event& event) {
   return true;
 }
 
+void OverviewButtonTray::SessionStateChanged(
+    SessionStateDelegate::SessionState state) {
+  UpdateIconVisibility();
+}
+
 void OverviewButtonTray::OnMaximizeModeStarted() {
   UpdateIconVisibility();
 }
@@ -115,9 +128,16 @@ void OverviewButtonTray::SetIconBorderForShelfAlignment() {
 }
 
 void OverviewButtonTray::UpdateIconVisibility() {
-  SetVisible(Shell::GetInstance()->maximize_mode_controller()->
-                 IsMaximizeModeWindowManagerEnabled() &&
-             Shell::GetInstance()->window_selector_controller()->CanSelect());
+  SetVisible(
+      Shell::GetInstance()
+          ->maximize_mode_controller()
+          ->IsMaximizeModeWindowManagerEnabled() &&
+      Shell::GetInstance()
+          ->session_state_delegate()
+          ->IsActiveUserSessionStarted() &&
+      !Shell::GetInstance()->session_state_delegate()->IsScreenLocked() &&
+      Shell::GetInstance()->session_state_delegate()->GetSessionState() ==
+          SessionStateDelegate::SESSION_STATE_ACTIVE);
 }
 
 }  // namespace ash