Focus first notification with ChromeVox shortcut

When Alt+Shift+N is used to open the message center, the first
notification will be focused with this change.
This fix is only available when the "Enable Message Center Redesign"
flag is enabled.

Bug: 1009485
Change-Id: I3509725aa76ad10d2a711c7cd923af4adc6ba31c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1859647Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Reviewed-by: Tim Song <tengs@chromium.org>
Commit-Queue: Ahmed Mehfooz <amehfooz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#705748}

ash/accelerators/accelerator_controller_impl.cc

@@ -596,7 +596,7 @@ void HandleTakeScreenshot() {
   Shell::Get()->screenshot_controller()->TakeScreenshotForAllRootWindows();
 }
 
-void HandleToggleSystemTrayBubbleInternal() {
+void HandleToggleSystemTrayBubbleInternal(bool focus_message_center) {
   aura::Window* target_root = Shell::GetRootWindowForNewWindows();
   UnifiedSystemTray* tray = RootWindowController::ForWindow(target_root)
                                 ->GetStatusAreaWidget()
@@ -606,17 +606,20 @@ void HandleToggleSystemTrayBubbleInternal() {
   } else {
     tray->ShowBubble(false /* show_by_click */);
     tray->ActivateBubble();
+
+    if (focus_message_center)
+      tray->FocusFirstNotification();
   }
 }
 
 void HandleToggleSystemTrayBubble() {
   base::RecordAction(UserMetricsAction("Accel_Toggle_System_Tray_Bubble"));
-  HandleToggleSystemTrayBubbleInternal();
+  HandleToggleSystemTrayBubbleInternal(false /*focus_message_center*/);
 }
 
 void HandleToggleMessageCenterBubble() {
   base::RecordAction(UserMetricsAction("Accel_Toggle_Message_Center_Bubble"));
-  HandleToggleSystemTrayBubbleInternal();
+  HandleToggleSystemTrayBubbleInternal(true /*focus_message_center*/);
 }
 
 void HandleShowTaskManager() {

ash/system/message_center/unified_message_center_bubble.cc

@@ -93,6 +93,10 @@ bool UnifiedMessageCenterBubble::FocusOut(bool reverse) {
   return tray_->FocusQuickSettings(reverse);
 }
 
+void UnifiedMessageCenterBubble::FocusFirstNotification() {
+  message_center_view_->GetFocusManager()->AdvanceFocus(false /*reverse*/);
+}
+
 bool UnifiedMessageCenterBubble::IsMessageCenterVisible() {
   return message_center_view_->GetVisible();
 }

ash/system/message_center/unified_message_center_bubble.h

@@ -38,6 +38,9 @@ class ASH_EXPORT UnifiedMessageCenterBubble : public TrayBubbleBase,
   // Relinquish focus and transfer it to the quick settings widget.
   bool FocusOut(bool reverse);
 
+  // Move focus to the first notification.
+  void FocusFirstNotification();
+
   // Returns true if notifications are shown.
   bool IsMessageCenterVisible();
 

ash/system/unified/unified_system_tray.cc

@@ -217,6 +217,14 @@ void UnifiedSystemTray::SetTrayBubbleHeight(int height) {
   ui_delegate_->SetTrayBubbleHeight(height);
 }
 
+void UnifiedSystemTray::FocusFirstNotification() {
+  if (!features::IsUnifiedMessageCenterRefactorEnabled())
+    return;
+
+  FocusMessageCenter(false /*reverse*/);
+  message_center_bubble()->FocusFirstNotification();
+}
+
 bool UnifiedSystemTray::FocusMessageCenter(bool reverse) {
   if (!IsMessageCenterBubbleShown())
     return false;

ash/system/unified/unified_system_tray.h

@@ -100,6 +100,9 @@ class ASH_EXPORT UnifiedSystemTray : public TrayBackgroundView,
   // bubble is shown.
   void SetTrayBubbleHeight(int height);
 
+  // Focus the first notification in the message center.
+  void FocusFirstNotification();
+
   bool FocusMessageCenter(bool reverse);
 
   bool FocusQuickSettings(bool reverse);