Move LayoutListBox::size() to HTMLSelectElement as ListBoxSize()

Also, this CL removes DEFINE_LAYOUT_OBJECT_TYPE_CASTS for LayoutListBox
because this CL removes the last usage of ToLayoutListBox().

This CL has no behavior changes.

Bug: 1040828
Change-Id: I0f531e1f059a3a85046711a1a11cb91450621069
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2040494
Commit-Queue: Kent Tamura <tkent@chromium.org>
Reviewed-by: Koji Ishii <kojii@chromium.org>
Reviewed-by: Yoshifumi Inoue <yosin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#738956}

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

@@ -92,6 +92,10 @@ namespace blink {
 // signed.
 static const unsigned kMaxListItems = INT_MAX;
 
+// Default size when the multiple attribute is present but size attribute is
+// absent.
+const int kDefaultListBoxSize = 4;
+
 HTMLSelectElement::HTMLSelectElement(Document& document)
     : HTMLFormControlElementWithState(html_names::kSelectTag, document),
       type_ahead_(this),
@@ -200,6 +204,14 @@ void HTMLSelectElement::SelectMultipleOptionsByPopup(
   ListBoxOnChange();
 }
 
+unsigned HTMLSelectElement::ListBoxSize() const {
+  DCHECK(!UsesMenuList());
+  const unsigned specified_size = size();
+  if (specified_size >= 1)
+    return specified_size;
+  return kDefaultListBoxSize;
+}
+
 bool HTMLSelectElement::UsesMenuList() const {
   if (LayoutTheme::GetTheme().DelegatesMenuListRendering())
     return true;
@@ -545,13 +557,10 @@ HTMLOptionElement* HTMLSelectElement::LastSelectableOption() const {
 HTMLOptionElement* HTMLSelectElement::NextSelectableOptionPageAway(
     HTMLOptionElement* start_option,
     SkipDirection direction) const {
+  DCHECK(!UsesMenuList());
   const ListItems& items = GetListItems();
-  // Can't use size_ because LayoutObject forces a minimum size.
-  int page_size = 0;
-  if (GetLayoutObject()->IsListBox()) {
-    // -1 so we still show context.
-    page_size = ToLayoutListBox(GetLayoutObject())->size() - 1;
-  }
+  // -1 so we still show context.
+  int page_size = ListBoxSize() - 1;
 
   // One page away, but not outside valid bounds.
   // If there is a valid option item one page away, the index is chosen.

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

@@ -75,6 +75,9 @@ class CORE_EXPORT HTMLSelectElement final
   // TODO(tkent): Rename |size| to |Size|. This is not an implementation of
   // |size| IDL attribute.
   unsigned size() const { return size_; }
+  // The number of items to be shown in the LisBox mode.
+  // Do not call this in the MenuList mode.
+  unsigned ListBoxSize() const;
   bool IsMultiple() const { return is_multiple_; }
 
   bool UsesMenuList() const;

third_party/blink/renderer/core/layout/layout_list_box.cc

@@ -43,10 +43,6 @@
 
 namespace blink {
 
-// Default size when the multiple attribute is present but size attribute is
-// absent.
-const int kDefaultSize = 4;
-
 const int kDefaultPaddingBottom = 1;
 
 LayoutListBox::LayoutListBox(Element* element) : LayoutBlockFlow(element) {
@@ -61,14 +57,6 @@ inline HTMLSelectElement* LayoutListBox::SelectElement() const {
   return To<HTMLSelectElement>(GetNode());
 }
 
-unsigned LayoutListBox::size() const {
-  unsigned specified_size = SelectElement()->size();
-  if (specified_size >= 1)
-    return specified_size;
-
-  return kDefaultSize;
-}
-
 LayoutUnit LayoutListBox::DefaultItemHeight() const {
   const SimpleFontData* font_data = StyleRef().GetFont().PrimaryFont();
   if (!font_data)
@@ -113,7 +101,7 @@ void LayoutListBox::ComputeLogicalHeight(
   if (HasOverrideIntrinsicContentLogicalHeight()) {
     height = OverrideIntrinsicContentLogicalHeight();
   } else {
-    height = ItemHeight() * size();
+    height = ItemHeight() * SelectElement()->ListBoxSize();
   }
 
   // FIXME: The item height should have been added before updateLogicalHeight

third_party/blink/renderer/core/layout/layout_list_box.h

@@ -42,8 +42,6 @@ class CORE_EXPORT LayoutListBox final : public LayoutBlockFlow {
   explicit LayoutListBox(Element*);
   ~LayoutListBox() override;
 
-  unsigned size() const;
-
   const char* GetName() const override { return "LayoutListBox"; }
 
  private:
@@ -64,8 +62,6 @@ class CORE_EXPORT LayoutListBox final : public LayoutBlockFlow {
   LayoutUnit ItemHeight() const;
 };
 
-DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutListBox, IsListBox());
-
 }  // namespace blink
 
 #endif  // THIRD_PARTY_BLINK_RENDERER_CORE_LAYOUT_LAYOUT_LIST_BOX_H_