Selects last item in a menu when pressing 'up' initially

ui/views/controls/menu/menu_controller.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/views/controls/menu/menu_controller.h"
 
 #include "base/i18n/case_conversion.h"
 #include "base/i18n/rtl.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/time/time.h"
@@ skipping 1886 matching lines @@
 }
 
 void MenuController::IncrementSelection(int delta) {
   MenuItemView* item = pending_state_.item;
   DCHECK(item);
   if (pending_state_.submenu_open && item->HasSubmenu() &&
       item->GetSubmenu()->IsShowing()) {
     // A menu is selected and open, but none of its children are selected,
     // select the first menu item that is visible and enabled.
     if (item->GetSubmenu()->GetMenuItemCount()) {
-      MenuItemView* to_select = FindFirstSelectableMenuItem(item);
+      MenuItemView* to_select = FindInitialSelectableMenuItem(item, delta);
       if (to_select)
         SetSelection(to_select, SELECTION_DEFAULT);
       return;
     }
   }
 
   if (item->has_children()) {
     CustomButton* button = GetFirstHotTrackedView(item);
     if (button) {
       button->SetHotTracked(false);
@@ skipping 28 matching lines @@
           CustomButton* button_hot = CustomButton::AsCustomButton(to_make_hot);
           if (button_hot)
             button_hot->SetHotTracked(true);
           break;
         }
       }
     }
   }
 }
 
-MenuItemView* MenuController::FindFirstSelectableMenuItem(
-    MenuItemView* parent) {
-  MenuItemView* child = parent->GetSubmenu()->GetMenuItemAt(0);
-  if (!child->visible() || !child->enabled())
-    child = FindNextSelectableMenuItem(parent, 0, 1);
-  return child;
+MenuItemView* MenuController::FindInitialSelectableMenuItem(
+    MenuItemView* parent,
+    int delta) {
+  return FindNextSelectableMenuItem(parent, delta > 0 ? -1 : 0, delta);
 }
 
 MenuItemView* MenuController::FindNextSelectableMenuItem(MenuItemView* parent,
                                                          int index,
                                                          int delta) {
-  int start_index = index;
   int parent_count = parent->GetSubmenu()->GetMenuItemCount();
+  int stop_index = (index + parent_count) % parent_count;
+  bool include_all_items = index + delta < 0 || index < 0;

[sadrul, 2015/07/15 19:21:52]

Hm, what's the use of |include_all_items|?

[varkha, 2015/07/15 19:51:34]

Just below. Normally we iterate on all but one current |index|. When
include_all_items is set (this happens for FindInitial calls) we need to
enumerate all items in hope of finding the first enabled (or the last for
reverse iteration).

   // Loop through the menu items skipping any invisible menus. The loop stops
   // when we wrap or find a visible and enabled child.
   do {
     index = (index + delta + parent_count) % parent_count;
-    if (index == start_index)
+    if (index == stop_index && !include_all_items)
       return NULL;
     MenuItemView* child = parent->GetSubmenu()->GetMenuItemAt(index);
     if (child->visible() && child->enabled())
       return child;
-  } while (index != start_index);
+  } while (index != stop_index);
   return NULL;
 }
 
 void MenuController::OpenSubmenuChangeSelectionIfCan() {
   MenuItemView* item = pending_state_.item;
   if (!item->HasSubmenu() || !item->enabled())
     return;
   MenuItemView* to_select = NULL;
   if (item->GetSubmenu()->GetMenuItemCount() > 0)
-    to_select = FindFirstSelectableMenuItem(item);
+    to_select = FindInitialSelectableMenuItem(item, 1);
   if (to_select) {
     SetSelection(to_select, SELECTION_UPDATE_IMMEDIATELY);
     return;
   }
   // No menu items, just show the sub-menu.
   SetSelection(item, SELECTION_OPEN_SUBMENU | SELECTION_UPDATE_IMMEDIATELY);
 }
 
 void MenuController::CloseSubmenu() {
   MenuItemView* item = state_.item;
@@ skipping 358 matching lines @@
   }
 }
 
 gfx::Screen* MenuController::GetScreen() {
   Widget* root = owner_ ? owner_->GetTopLevelWidget() : NULL;
   return root ? gfx::Screen::GetScreenFor(root->GetNativeView())
               : gfx::Screen::GetNativeScreen();
 }
 
 }  // namespace views