Stop the OverviewButton from appearing on the Add-User screen

OverviewButtonTray was showing up on the Add-User screen. It should only be
available when a user is logged in and in the active state.

Update OverviewButtonTray to observe SessionState changes to determine
visibility.

Update WindowSelectorController to not allow overview mode while on the
add-user screen.

TEST=OverviewButtonTrayTest.VisibilityChangesForLoginStatus
BUG=488464, 482591

Review URL: https://codereview.chromium.org/1149833006

Cr-Commit-Position: refs/heads/master@{#332872}

3 files changed, 71 insertions, 4 deletions

diff --git a/ash/system/overview/overview_button_tray.cc b/ash/system/overview/overview_button_tray.cc
index edd5d67..f5295b5 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"
@@ -42,10 +43,13 @@ 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(
@@ -62,6 +66,11 @@ bool OverviewButtonTray::PerformAction(const ui::Event& event) {
   return true;
 }
 
+void OverviewButtonTray::SessionStateChanged(
+    SessionStateDelegate::SessionState state) {
+  UpdateIconVisibility();
+}
+
 void OverviewButtonTray::OnMaximizeModeStarted() {
   UpdateIconVisibility();
 }
@@ -115,9 +124,22 @@ void OverviewButtonTray::SetIconBorderForShelfAlignment() {
 }
 
 void OverviewButtonTray::UpdateIconVisibility() {
-  SetVisible(Shell::GetInstance()->maximize_mode_controller()->
-                 IsMaximizeModeWindowManagerEnabled() &&
-             Shell::GetInstance()->window_selector_controller()->CanSelect());
+  // The visibility of the OverviewButtonTray has diverge from
+  // WindowSelectorController::CanSelect. The visibility of the button should
+  // not change during transient times in which CanSelect is false. Such as when
+  // a modal dialog is present.
+  Shell* shell = Shell::GetInstance();
+  SessionStateDelegate* session_state_delegate =
+      shell->session_state_delegate();
+
+  SetVisible(
+      shell->maximize_mode_controller()->IsMaximizeModeWindowManagerEnabled() &&
+      session_state_delegate->IsActiveUserSessionStarted() &&
+      !session_state_delegate->IsScreenLocked() &&
+      session_state_delegate->GetSessionState() ==
+          SessionStateDelegate::SESSION_STATE_ACTIVE &&
+      shell->system_tray_delegate()->GetUserLoginStatus() !=
+          user::LOGGED_IN_KIOSK_APP);
 }
 
 }  // namespace ash
diff --git a/ash/system/overview/overview_button_tray.h b/ash/system/overview/overview_button_tray.h
index a58bae1..d3988be 100644
--- a/ash/system/overview/overview_button_tray.h
+++ b/ash/system/overview/overview_button_tray.h
@@ -6,9 +6,9 @@
 #define ASH_SYSTEM_OVERVIEW_OVERVIEW_BUTTON_TRAY_H_
 
 #include "ash/ash_export.h"
+#include "ash/session/session_state_observer.h"
 #include "ash/shell_observer.h"
 #include "ash/system/tray/tray_background_view.h"
-#include "ash/wm/overview/window_selector_controller.h"
 
 namespace views {
 class ImageView;
@@ -22,6 +22,7 @@ namespace ash {
 // This tray will only be visible while in this state. This tray does not
 // provide any bubble view windows.
 class ASH_EXPORT OverviewButtonTray : public TrayBackgroundView,
+                                      public SessionStateObserver,
                                       public ShellObserver {
  public:
   explicit OverviewButtonTray(StatusAreaWidget* status_area_widget);
@@ -34,6 +35,9 @@ class ASH_EXPORT OverviewButtonTray : public TrayBackgroundView,
   // ActionableView:
   bool PerformAction(const ui::Event& event) override;
 
+  // SessionStateObserver:
+  void SessionStateChanged(SessionStateDelegate::SessionState state) override;
+
   // ShellObserver:
   void OnMaximizeModeStarted() override;
   void OnMaximizeModeEnded() override;
diff --git a/ash/system/overview/overview_button_tray_unittest.cc b/ash/system/overview/overview_button_tray_unittest.cc
index a7e6a3e..4468aae 100644
--- a/ash/system/overview/overview_button_tray_unittest.cc
+++ b/ash/system/overview/overview_button_tray_unittest.cc
@@ -14,12 +14,16 @@
 #include "ash/system/status_area_widget.h"
 #include "ash/system/user/login_status.h"
 #include "ash/test/ash_test_base.h"
+#include "ash/test/ash_test_helper.h"
 #include "ash/test/status_area_widget_test_helper.h"
+#include "ash/test/test_session_state_delegate.h"
 #include "ash/wm/maximize_mode/maximize_mode_controller.h"
 #include "ash/wm/overview/window_selector_controller.h"
 #include "base/command_line.h"
 #include "base/test/user_action_tester.h"
 #include "base/time/time.h"
+#include "ui/aura/client/aura_constants.h"
+#include "ui/aura/window.h"
 #include "ui/compositor/scoped_animation_duration_scale_mode.h"
 #include "ui/events/event.h"
 #include "ui/events/event_constants.h"
@@ -51,6 +55,8 @@ class OverviewButtonTrayTest : public test::AshTestBase {
 
   void SetUp() override;
 
+  void NotifySessionStateChanged();
+
  protected:
   views::ImageView* GetImageView(OverviewButtonTray* tray) {
     return tray->icon_;
@@ -68,6 +74,11 @@ void OverviewButtonTrayTest::SetUp() {
   AshTestBase::SetUp();
 }
 
+void OverviewButtonTrayTest::NotifySessionStateChanged() {
+  GetTray()->SessionStateChanged(
+      ash_test_helper()->GetTestSessionStateDelegate()->GetSessionState());
+}
+
 // Ensures that creation doesn't cause any crashes and adds the image icon.
 TEST_F(OverviewButtonTrayTest, BasicConstruction) {
   EXPECT_TRUE(GetImageView(GetTray()) != NULL);
@@ -178,6 +189,12 @@ TEST_F(OverviewButtonTrayTest, VisibilityChangesForLoginStatus) {
   SetSessionStarted(true);
   Shell::GetInstance()->UpdateAfterLoginStatusChange(user::LOGGED_IN_USER);
   EXPECT_TRUE(GetTray()->visible());
+  SetUserAddingScreenRunning(true);
+  NotifySessionStateChanged();
+  EXPECT_FALSE(GetTray()->visible());
+  SetUserAddingScreenRunning(false);
+  NotifySessionStateChanged();
+  EXPECT_TRUE(GetTray()->visible());
   Shell::GetInstance()->maximize_mode_controller()->
       EnableMaximizeModeWindowManager(false);
 }
@@ -230,4 +247,28 @@ TEST_F(OverviewButtonTrayTest, HideAnimationAlwaysCompletes) {
   EXPECT_FALSE(GetTray()->visible());
 }
 
+// Tests that the overview button becomes visible when the user enters
+// maximize mode with a system modal window open, and that it hides once
+// the user exits maximize mode.
+TEST_F(OverviewButtonTrayTest, VisibilityChangesForSystemModalWindow) {
+  // TODO(jonross): When CreateTestWindow*() have been unified, use the
+  // appropriate method to replace this setup. (crbug.com/483503)
+  scoped_ptr<aura::Window> window(new aura::Window(nullptr));
+  window->SetProperty(aura::client::kModalKey, ui::MODAL_TYPE_SYSTEM);
+  window->SetType(ui::wm::WINDOW_TYPE_NORMAL);
+  window->Init(ui::LAYER_TEXTURED);
+  window->Show();
+  ParentWindowInPrimaryRootWindow(window.get());
+
+  ASSERT_TRUE(Shell::GetInstance()->IsSystemModalWindowOpen());
+  Shell::GetInstance()
+      ->maximize_mode_controller()
+      ->EnableMaximizeModeWindowManager(true);
+  EXPECT_TRUE(GetTray()->visible());
+  Shell::GetInstance()
+      ->maximize_mode_controller()
+      ->EnableMaximizeModeWindowManager(false);
+  EXPECT_FALSE(GetTray()->visible());
+}
+
 }  // namespace ash