Introduce blink::SelectType

This CL introduces blink::SelectType, blink::MenuListSelectType, and
blink::ListBoxSelectType.
Also, add SelectType::DidSelectOption() to simplify
HTMLSelectElement::SelectOption().

This CL has no behavior changes.

Bug: 1052232
Change-Id: I436cfdd70edf0668b03996b35008ae12f8b6c9c3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2055950Reviewed-by: Koji Ishii <kojii@chromium.org>
Commit-Queue: Kent Tamura <tkent@chromium.org>
Cr-Commit-Position: refs/heads/master@{#741383}

third_party/blink/renderer/core/html/BUILD.gn

@@ -247,6 +247,8 @@ blink_core_sources("html") {
     "forms/reset_input_type.h",
     "forms/search_input_type.cc",
     "forms/search_input_type.h",
+    "forms/select_type.cc",
+    "forms/select_type.h",
     "forms/slider_thumb_element.cc",
     "forms/slider_thumb_element.h",
     "forms/spin_button_element.cc",

third_party/blink/renderer/core/html/forms/html_select_element.cc

@@ -60,6 +60,7 @@
 #include "third_party/blink/renderer/core/html/forms/html_option_element.h"
 #include "third_party/blink/renderer/core/html/forms/menu_list_inner_element.h"
 #include "third_party/blink/renderer/core/html/forms/popup_menu.h"
+#include "third_party/blink/renderer/core/html/forms/select_type.h"
 #include "third_party/blink/renderer/core/html/html_hr_element.h"
 #include "third_party/blink/renderer/core/html/html_slot_element.h"
 #include "third_party/blink/renderer/core/html/parser/html_parser_idioms.h"
@@ -107,6 +108,8 @@ HTMLSelectElement::HTMLSelectElement(Document& document)
       is_autofilled_by_preview_(false),
       index_to_select_on_cancel_(-1),
       popup_is_visible_(false) {
+  // Make sure SelectType is created after initializing |uses_menu_list_|.
+  select_type_ = SelectType::Create(*this);
   SetHasCustomStyleCallbacks();
   EnsureUserAgentShadowRoot();
 }
@@ -1089,40 +1092,7 @@ void HTMLSelectElement::SelectOption(HTMLOptionElement* element,
       SetActiveSelectionEnd(element);
   }
 
-  // Need to update last_on_change_option_ before
-  // LayoutMenuList::UpdateFromElement.
-  bool should_dispatch_events = false;
-  if (UsesMenuList()) {
-    should_dispatch_events = (flags & kDispatchInputAndChangeEventFlag) &&
-                             last_on_change_option_ != element;
-    last_on_change_option_ = element;
-  }
-
-  // For the menu list case, this is what makes the selected element appear.
-  UpdateMenuListLabel(UpdateFromElement());
-  // PopupMenu::UpdateFromElement() posts an O(N) task.
-  if (PopupIsVisible() && should_update_popup)
-    popup_->UpdateFromElement(PopupMenu::kBySelectionChange);
-
-  ScrollToSelection();
-  SetNeedsValidityCheck();
-
-  if (UsesMenuList()) {
-    if (should_dispatch_events) {
-      DispatchInputEvent();
-      DispatchChangeEvent();
-    }
-    if (LayoutObject* layout_object = GetLayoutObject()) {
-      // Need to check UsesMenuList() again because event handlers might
-      // change the status.
-      if (UsesMenuList()) {
-        // DidUpdateMenuListActiveOption() is O(N) because of
-        // HTMLOptionElement::index().
-        DidUpdateMenuListActiveOption(element);
-      }
-    }
-  }
-
+  select_type_->DidSelectOption(element, flags, should_update_popup);
   NotifyFormStateChanged();
 
   if (LocalFrame::HasTransientUserActivation(GetDocument().GetFrame()) &&
@@ -1983,6 +1953,7 @@ void HTMLSelectElement::Trace(Visitor* visitor) {
   visitor->Trace(active_selection_end_);
   visitor->Trace(option_to_scroll_to_);
   visitor->Trace(suggested_option_);
+  visitor->Trace(select_type_);
   visitor->Trace(popup_);
   visitor->Trace(popup_updater_);
   HTMLFormControlElementWithState::Trace(visitor);
@@ -2290,6 +2261,7 @@ void HTMLSelectElement::CloneNonAttributePropertiesFrom(
 
 void HTMLSelectElement::ChangeRendering() {
   UpdateUsesMenuList();
+  select_type_ = SelectType::Create(*this);
   if (!InActiveDocument())
     return;
   // TODO(futhark): SetForceReattachLayoutTree() should be the correct way to

third_party/blink/renderer/core/html/forms/html_select_element.h

@@ -47,6 +47,7 @@ class HTMLOptionElementOrHTMLOptGroupElement;
 class HTMLElementOrLong;
 class LayoutUnit;
 class PopupMenu;
+class SelectType;
 
 class CORE_EXPORT HTMLSelectElement final
     : public HTMLFormControlElementWithState,
@@ -333,12 +334,16 @@ class CORE_EXPORT HTMLSelectElement final
   mutable bool should_recalc_list_items_;
   bool is_autofilled_by_preview_;
 
+  Member<SelectType> select_type_;
   class PopupUpdater;
   Member<PopupUpdater> popup_updater_;
   Member<PopupMenu> popup_;
   int index_to_select_on_cancel_;
   bool popup_is_visible_;
 
+  friend class ListBoxSelectType;
+  friend class MenuListSelectType;
+  friend class SelectType;
   FRIEND_TEST_ALL_PREFIXES(HTMLSelectElementTest, FirstSelectableOption);
   FRIEND_TEST_ALL_PREFIXES(HTMLSelectElementTest, LastSelectableOption);
   FRIEND_TEST_ALL_PREFIXES(HTMLSelectElementTest, NextSelectableOption);

third_party/blink/renderer/core/html/forms/select_type.cc

+/*
+ * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
+ * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
+ *           (C) 1999 Antti Koivisto (koivisto@kde.org)
+ *           (C) 2001 Dirk Mueller (mueller@kde.org)
+ * Copyright (C) 2004, 2005, 2006, 2007, 2009, 2010, 2011 Apple Inc. All rights
+ * reserved.
+ *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
+ * Copyright (C) 2010 Google Inc. All rights reserved.
+ * Copyright (C) 2009 Torch Mobile Inc. All rights reserved.
+ * (http://www.torchmobile.com/)
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public License
+ * along with this library; see the file COPYING.LIB.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ *
+ */
+
+#include "third_party/blink/renderer/core/html/forms/select_type.h"
+
+#include "third_party/blink/renderer/core/html/forms/html_select_element.h"
+#include "third_party/blink/renderer/core/html/forms/popup_menu.h"
+
+namespace blink {
+
+class MenuListSelectType : public SelectType {
+ public:
+  explicit MenuListSelectType(HTMLSelectElement& select) : SelectType(select) {}
+
+  void DidSelectOption(HTMLOptionElement* element,
+                       HTMLSelectElement::SelectOptionFlags flags,
+                       bool should_update_popup) override;
+};
+
+void MenuListSelectType::DidSelectOption(
+    HTMLOptionElement* element,
+    HTMLSelectElement::SelectOptionFlags flags,
+    bool should_update_popup) {
+  // Need to update last_on_change_option_ before UpdateFromElement().
+  const bool should_dispatch_events =
+      (flags & HTMLSelectElement::kDispatchInputAndChangeEventFlag) &&
+      select_->last_on_change_option_ != element;
+  select_->last_on_change_option_ = element;
+
+  select_->UpdateMenuListLabel(select_->UpdateFromElement());
+  // PopupMenu::UpdateFromElement() posts an O(N) task.
+  if (select_->PopupIsVisible() && should_update_popup)
+    select_->popup_->UpdateFromElement(PopupMenu::kBySelectionChange);
+
+  SelectType::DidSelectOption(element, flags, should_update_popup);
+
+  if (should_dispatch_events) {
+    select_->DispatchInputEvent();
+    select_->DispatchChangeEvent();
+  }
+  if (select_->GetLayoutObject()) {
+    // Need to check UsesMenuList() again because event handlers might
+    // change the status.
+    if (select_->UsesMenuList()) {
+      // DidUpdateMenuListActiveOption() is O(N) because of
+      // HTMLOptionElement::index().
+      select_->DidUpdateMenuListActiveOption(element);
+    }
+  }
+}
+
+// ============================================================================
+
+class ListBoxSelectType : public SelectType {
+ public:
+  explicit ListBoxSelectType(HTMLSelectElement& select) : SelectType(select) {}
+};
+
+// ============================================================================
+
+SelectType::SelectType(HTMLSelectElement& select) : select_(select) {}
+
+SelectType* SelectType::Create(HTMLSelectElement& select) {
+  if (select.UsesMenuList())
+    return MakeGarbageCollected<MenuListSelectType>(select);
+  else
+    return MakeGarbageCollected<ListBoxSelectType>(select);
+}
+
+void SelectType::Trace(Visitor* visitor) {
+  visitor->Trace(select_);
+}
+
+void SelectType::DidSelectOption(HTMLOptionElement*,
+                                 HTMLSelectElement::SelectOptionFlags,
+                                 bool) {
+  select_->ScrollToSelection();
+  select_->SetNeedsValidityCheck();
+}
+
+}  // namespace blink

third_party/blink/renderer/core/html/forms/select_type.h

+// Copyright 2020 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.
+
+#ifndef THIRD_PARTY_BLINK_RENDERER_CORE_HTML_FORMS_SELECT_TYPE_H_
+#define THIRD_PARTY_BLINK_RENDERER_CORE_HTML_FORMS_SELECT_TYPE_H_
+
+#include "third_party/blink/renderer/core/html/forms/html_select_element.h"
+#include "third_party/blink/renderer/platform/heap/handle.h"
+
+namespace blink {
+
+// SelectType class is an abstraction of the MenuList behavior and the ListBox
+// behavior of HTMLSelectElement.
+class SelectType : public GarbageCollected<SelectType> {
+ public:
+  // Creates an instance of a SelectType subclass depending on the current mode
+  // of |select|.
+  static SelectType* Create(HTMLSelectElement& select);
+  virtual void Trace(Visitor* visitor);
+
+  virtual void DidSelectOption(HTMLOptionElement* element,
+                               HTMLSelectElement::SelectOptionFlags flags,
+                               bool should_update_popup);
+
+  // TODO(crbug.com/1052232): Add more virtual functions.
+
+ protected:
+  explicit SelectType(HTMLSelectElement& select);
+
+  Member<HTMLSelectElement> select_;
+
+ private:
+  SelectType(const SelectType&) = delete;
+  SelectType& operator=(const SelectType&) = delete;
+};
+
+}  // namespace blink
+#endif  // THIRD_PARTY_BLINK_RENDERER_CORE_HTML_FORMS_SELECT_TYPE_H_