Allowing keyboard focus for Quick-Answers on Up key

This CL modifies the way users can gain keyboard focus to Quick-Answers
related views by pressing the Up key after a menu has been opened.
Currently, pressing the Up key selects the last menu-item in the active
menu, from which QuickAnswersView can be accessed by pressing the Down
key again.

Bug: b:152057976
Test: Tested on Chrome OS VM.
Change-Id: Ib435d867ca7b70017531d5b8a1b3f5aa6cd577b1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2271071
Commit-Queue: Abhijeet Singh <siabhijeet@google.com>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#783662}

ash/quick_answers/ui/quick_answers_pre_target_handler.cc

@@ -169,24 +169,36 @@ void QuickAnswersPreTargetHandler::ProcessKeyEvent(ui::KeyEvent* key_event) {
       // Get the selected item, if any, in the currently active menu.
       auto* const active_menu = views::MenuController::GetActiveInstance();
       auto* const selected_item = active_menu->GetSelectedMenuItem();
-      if (!selected_item || !selected_item->GetParentMenuItem())
+      if (!selected_item)
         return;
 
-      // Check if the item is within the outer-most menu, since we do not want
-      // the selection to loop back to |view_| for submenus.
       const auto* const parent = selected_item->GetParentMenuItem();
-      if (parent->GetParentMenuItem())
-        return;
-
-      // Check if the selected item is first or last within the menu.
-      bool is_first = selected_item == parent->GetSubmenu()->children().front();
-      bool is_last = selected_item == parent->GetSubmenu()->children().back();
-      if (!is_first && !is_last)
-        return;
+      bool view_should_gain_focus = false;
+      if (parent) {
+        // Check if the item is within the outer-most menu, since we do not want
+        // the selection to loop back to |view_| for submenus.
+        if (parent->GetParentMenuItem())
+          return;
+
+        // |view_| should gain focus only when the selected item is first or
+        // last within the menu.
+        bool first_item_selected =
+            selected_item == parent->GetSubmenu()->children().front();
+        bool last_item_selected =
+            selected_item == parent->GetSubmenu()->children().back();
+        view_should_gain_focus =
+            (first_item_selected || last_item_selected) &&
+            first_item_selected == (key_code == ui::VKEY_UP);
+      } else {
+        // Selected menu-item will have no parent only when there are no nested
+        // menus and no items are visibly selected, and |view_| should gain
+        // focus for Up-key press in such scenario.
+        view_should_gain_focus = key_code == ui::VKEY_UP;
+      }
 
       // Focus |view_| if compatible key-event should transfer the selection to
       // it from within the menu.
-      if (is_first == (key_code == ui::VKEY_UP)) {
+      if (view_should_gain_focus) {
         // Track currently focused view to restore back to later and send focus
         // to |view_|.
         external_focus_tracker_->SetFocusManager(focus_manager);