Fix tab focusing to system tray in OOBE screen.

Recently, UnifiedSystemTray replaced SystemTray class.
WebUILoginView ignored UnifiedSystemTray because I misunderstood
views login will completely replace WebUILoginView. However,
WebUILoginView is still used in OOBE screen, so we should fix it to also
work with UnifiedSystemTray.

TEST=manual
BUG=853713

Change-Id: I3842eba971a928af5ba1599283c52f9711d83cc4
Reviewed-on: https://chromium-review.googlesource.com/1107520
Commit-Queue: Tetsui Ohkubo <tetsui@chromium.org>
Reviewed-by: James Cook <jamescook@chromium.org>
Cr-Commit-Position: refs/heads/master@{#570996}

ash/root_window_controller.cc

@@ -38,6 +38,9 @@
 #include "ash/shell_state.h"
 #include "ash/system/status_area_layout_manager.h"
 #include "ash/system/status_area_widget.h"
+#include "ash/system/tray/system_tray.h"
+#include "ash/system/tray/tray_background_view.h"
+#include "ash/system/unified/unified_system_tray.h"
 #include "ash/touch/touch_hud_debug.h"
 #include "ash/touch/touch_hud_projection.h"
 #include "ash/touch/touch_observer_hud.h"
@@ -395,6 +398,15 @@ SystemTray* RootWindowController::GetSystemTray() {
   return shelf_->shelf_widget()->status_area_widget()->system_tray();
 }
 
+bool RootWindowController::IsSystemTrayVisible() {
+  TrayBackgroundView* tray = nullptr;
+  if (features::IsSystemTrayUnifiedEnabled())
+    tray = GetStatusAreaWidget()->unified_system_tray();
+  else
+    tray = GetSystemTray();
+  return tray && tray->GetWidget()->IsVisible() && tray->visible();
+}
+
 bool RootWindowController::CanWindowReceiveEvents(aura::Window* window) {
   if (GetRootWindow() != window->GetRootWindow())
     return false;

ash/root_window_controller.h

@@ -169,6 +169,9 @@ class ASH_EXPORT RootWindowController {
   // lead to a crash.
   SystemTray* GetSystemTray();
 
+  // Returns if system tray and its widget is visible.
+  bool IsSystemTrayVisible();
+
   // True if the window can receive events on this root window.
   bool CanWindowReceiveEvents(aura::Window* window);
 

chrome/browser/chromeos/login/ui/webui_login_view.cc

@@ -573,10 +573,6 @@ bool WebUILoginView::MoveFocusToSystemTray(bool reverse) {
   if (!features::IsAshInBrowserProcess())
     return true;
 
-  // The old system tray is not available when UnifiedSystemTray is enabled.
-  if (ash::features::IsSystemTrayUnifiedEnabled())
-    return true;
-
   // The focus should not move to the system tray if voice interaction OOOBE is
   // active.
   if (LoginDisplayHost::default_host() &&
@@ -595,10 +591,9 @@ bool WebUILoginView::MoveFocusToSystemTray(bool reverse) {
     return true;
   }
 
-  ash::SystemTray* tray =
-      ash::RootWindowController::ForWindow(GetWidget()->GetNativeWindow())
-          ->GetSystemTray();
-  if (!tray || !tray->GetWidget()->IsVisible() || !tray->visible())
+  ash::RootWindowController* primary_controller =
+      ash::RootWindowController::ForWindow(GetWidget()->GetNativeWindow());
+  if (!primary_controller->IsSystemTrayVisible())
     return false;
 
   shelf->GetStatusAreaWidget()