Unified: Disable user chooser btn with single user

In the old SystemTray, user button was not focusable when there was only
one user account on the device.

TEST=manual
BUG=863337

Change-Id: I8373b144371fce060c454ae07e7456f1fe914a4f
Reviewed-on: https://chromium-review.googlesource.com/1164869Reviewed-by: Yoshiki Iguchi <yoshiki@chromium.org>
Commit-Queue: Tetsui Ohkubo <tetsui@chromium.org>
Cr-Commit-Position: refs/heads/master@{#581429}

ash/system/unified/top_shortcuts_view.cc

@@ -146,6 +146,7 @@ TopShortcutsView::TopShortcutsView(UnifiedSystemTrayController* controller)
   if (Shell::Get()->session_controller()->login_status() !=
       LoginStatus::NOT_LOGGED_IN) {
     user_avatar_button_ = new UserAvatarButton(this);
+    user_avatar_button_->SetEnabled(controller->IsUserChooserEnabled());
     container_->AddChildView(user_avatar_button_);
   }
 
@@ -198,7 +199,7 @@ void TopShortcutsView::SetExpandedAmount(double expanded_amount) {
 void TopShortcutsView::ButtonPressed(views::Button* sender,
                                      const ui::Event& event) {
   if (sender == user_avatar_button_)
-    controller_->ShowUserChooserWidget();
+    controller_->ShowUserChooserView();
   else if (sender == sign_out_button_)
     controller_->HandleSignOutAction();
   else if (sender == lock_button_)

ash/system/unified/unified_system_tray_controller.cc

@@ -213,22 +213,9 @@ void UnifiedSystemTrayController::Fling(int velocity) {
   StartAnimation(velocity < 0);
 }
 
-void UnifiedSystemTrayController::ShowUserChooserWidget() {
-  // Don't allow user add or switch when CancelCastingDialog is open.
-  // See http://crrev.com/291276 and http://crbug.com/353170.
-  if (Shell::IsSystemModalWindowOpen())
-    return;
-
-  // Don't allow at login, lock or when adding a multi-profile user.
-  SessionController* session = Shell::Get()->session_controller();
-  if (session->IsUserSessionBlocked())
+void UnifiedSystemTrayController::ShowUserChooserView() {
+  if (!IsUserChooserEnabled())
     return;
-
-  // Don't show if we cannot add or switch users.
-  if (session->GetAddUserPolicy() != AddUserSessionPolicy::ALLOWED &&
-      session->NumberOfLoggedInUsers() <= 1)
-    return;
-
   unified_view_->SetDetailedView(new UserChooserView(this));
 }
 
@@ -305,6 +292,24 @@ void UnifiedSystemTrayController::EnsureExpanded() {
   animation_->Show();
 }
 
+bool UnifiedSystemTrayController::IsUserChooserEnabled() const {
+  // Don't allow user add or switch when CancelCastingDialog is open.
+  // See http://crrev.com/291276 and http://crbug.com/353170.
+  if (Shell::IsSystemModalWindowOpen())
+    return false;
+
+  // Don't allow at login, lock or when adding a multi-profile user.
+  SessionController* session = Shell::Get()->session_controller();
+  if (session->IsUserSessionBlocked())
+    return false;
+
+  // Don't show if we cannot add or switch users.
+  if (session->GetAddUserPolicy() != AddUserSessionPolicy::ALLOWED &&
+      session->NumberOfLoggedInUsers() <= 1)
+    return false;
+  return true;
+}
+
 void UnifiedSystemTrayController::AnimationEnded(
     const gfx::Animation* animation) {
   UpdateExpandedAmount();

ash/system/unified/unified_system_tray_controller.h

@@ -69,8 +69,8 @@ class ASH_EXPORT UnifiedSystemTrayController : public gfx::AnimationDelegate {
   void EndDrag(const gfx::Point& location);
   void Fling(int velocity);
 
-  // Show user selector popup widget. Called from the view.
-  void ShowUserChooserWidget();
+  // Show user selector view. Called from the view.
+  void ShowUserChooserView();
   // Show the detailed view of network. If |force| is true, it shows the
   // detailed view even if it's collapsed. Called from the view.
   void ShowNetworkDetailedView(bool force);
@@ -103,6 +103,9 @@ class ASH_EXPORT UnifiedSystemTrayController : public gfx::AnimationDelegate {
   // Ensure the main view is expanded. Called from the slider bubble controller.
   void EnsureExpanded();
 
+  // Return true if user chooser is enabled. Called from the view.
+  bool IsUserChooserEnabled() const;
+
   // gfx::AnimationDelegate:
   void AnimationEnded(const gfx::Animation* animation) override;
   void AnimationProgressed(const gfx::Animation* animation) override;