LibHTML: Add stub classes for basic table layout

This class introduces LayoutTable, LayoutTableRow and LayoutTableCell.
These are produced by "display" values table, table-row and table-cell
respectively.

Note that there's no layout happening yet, I'm just adding the classes.

Libraries/LibHTML/CSS/Default.css

@@ -109,3 +109,15 @@ hr {
 blink {
     display: inline;
 }
+
+table {
+    display: table;
+}
+
+tr {
+    display: table-row;
+}
+
+td {
+    display: table-cell;
+}

Libraries/LibHTML/DOM/Element.cpp

@@ -4,6 +4,9 @@
 #include <LibHTML/Layout/LayoutBlock.h>
 #include <LibHTML/Layout/LayoutInline.h>
 #include <LibHTML/Layout/LayoutListItem.h>
+#include <LibHTML/Layout/LayoutTable.h>
+#include <LibHTML/Layout/LayoutTableCell.h>
+#include <LibHTML/Layout/LayoutTableRow.h>
 
 Element::Element(Document& document, const String& tag_name)
     : ParentNode(document, NodeType::ELEMENT_NODE)
@@ -84,6 +87,12 @@ RefPtr<LayoutNode> Element::create_layout_node(const StyleProperties* parent_sty
         return adopt(*new LayoutInline(*this, move(style)));
     if (display == "list-item")
         return adopt(*new LayoutListItem(*this, move(style)));
+    if (display == "table")
+        return adopt(*new LayoutTable(*this, move(style)));
+    if (display == "table-row")
+        return adopt(*new LayoutTableRow(*this, move(style)));
+    if (display == "table-cell")
+        return adopt(*new LayoutTableCell(*this, move(style)));
 
     ASSERT_NOT_REACHED();
 }

Libraries/LibHTML/Layout/LayoutTable.cpp

@@ -0,0 +1,16 @@
+#include <LibHTML/DOM/Element.h>
+#include <LibHTML/Layout/LayoutTable.h>
+
+LayoutTable::LayoutTable(const Element& element, NonnullRefPtr<StyleProperties> style)
+    : LayoutBlock(&element, move(style))
+{
+}
+
+LayoutTable::~LayoutTable()
+{
+}
+
+void LayoutTable::layout()
+{
+    LayoutBlock::layout();
+}

Libraries/LibHTML/Layout/LayoutTable.h

@@ -0,0 +1,14 @@
+#pragma once
+
+#include <LibHTML/Layout/LayoutBlock.h>
+
+class LayoutTable final : public LayoutBlock {
+public:
+    LayoutTable(const Element&, NonnullRefPtr<StyleProperties>);
+    virtual ~LayoutTable() override;
+
+    virtual void layout() override;
+
+private:
+    virtual const char* class_name() const override { return "LayoutTable"; }
+};

Libraries/LibHTML/Layout/LayoutTableCell.cpp

@@ -0,0 +1,11 @@
+#include <LibHTML/DOM/Element.h>
+#include <LibHTML/Layout/LayoutTableCell.h>
+
+LayoutTableCell::LayoutTableCell(const Element& element, NonnullRefPtr<StyleProperties> style)
+    : LayoutBlock(&element, move(style))
+{
+}
+
+LayoutTableCell::~LayoutTableCell()
+{
+}

Libraries/LibHTML/Layout/LayoutTableCell.h

@@ -0,0 +1,12 @@
+#pragma once
+
+#include <LibHTML/Layout/LayoutBlock.h>
+
+class LayoutTableCell final : public LayoutBlock {
+public:
+    LayoutTableCell(const Element&, NonnullRefPtr<StyleProperties>);
+    virtual ~LayoutTableCell() override;
+
+private:
+    virtual const char* class_name() const override { return "LayoutTableCell"; }
+};

Libraries/LibHTML/Layout/LayoutTableRow.cpp

@@ -0,0 +1,16 @@
+#include <LibHTML/DOM/Element.h>
+#include <LibHTML/Layout/LayoutTableRow.h>
+
+LayoutTableRow::LayoutTableRow(const Element& element, NonnullRefPtr<StyleProperties> style)
+    : LayoutBox(&element, move(style))
+{
+}
+
+LayoutTableRow::~LayoutTableRow()
+{
+}
+
+void LayoutTableRow::layout()
+{
+    LayoutBox::layout();
+}

Libraries/LibHTML/Layout/LayoutTableRow.h

@@ -0,0 +1,14 @@
+#pragma once
+
+#include <LibHTML/Layout/LayoutBox.h>
+
+class LayoutTableRow final : public LayoutBox {
+public:
+    LayoutTableRow(const Element&, NonnullRefPtr<StyleProperties>);
+    virtual ~LayoutTableRow() override;
+
+    virtual void layout() override;
+
+private:
+    virtual const char* class_name() const override { return "LayoutTableRow"; }
+};

Libraries/LibHTML/Makefile.shared

@@ -44,6 +44,9 @@ LIBHTML_OBJS = \
     Layout/LayoutListItem.o \
     Layout/LayoutListItemMarker.o \
     Layout/LayoutBreak.o \
+    Layout/LayoutTable.o \
+    Layout/LayoutTableRow.o \
+    Layout/LayoutTableCell.o \
     Layout/BoxModelMetrics.o \
     Layout/LineBox.o \
     Layout/LineBoxFragment.o \