LibHTML: Flesh out <img> element with LayoutImage and LayoutReplaced

This patch adds parsing of <img> into HTMLImageElement objects.
It also adds LayoutImage and its parent class LayoutReplaced, which is
going to represent CSS "replaced elements."

Libraries/LibHTML/Layout/LayoutImage.cpp

@@ -0,0 +1,20 @@
+#include <LibHTML/Layout/LayoutImage.h>
+
+LayoutImage::LayoutImage(const HTMLImageElement& element, NonnullRefPtr<StyleProperties> style)
+    : LayoutReplaced(element, move(style))
+{
+}
+
+LayoutImage::~LayoutImage()
+{
+}
+
+void LayoutImage::layout()
+{
+    LayoutReplaced::layout();
+}
+
+void LayoutImage::render(RenderingContext& context)
+{
+    LayoutReplaced::render(context);
+}

Libraries/LibHTML/Layout/LayoutImage.h

@@ -0,0 +1,18 @@
+#pragma once
+
+#include <LibHTML/DOM/HTMLImageElement.h>
+#include <LibHTML/Layout/LayoutReplaced.h>
+
+class HTMLImageElement;
+
+class LayoutImage : public LayoutReplaced {
+public:
+    LayoutImage(const HTMLImageElement&, NonnullRefPtr<StyleProperties>);
+    virtual ~LayoutImage() override;
+
+    virtual void layout() override;
+    virtual void render(RenderingContext&) override;
+
+    const HTMLImageElement& node() const { return static_cast<const HTMLImageElement&>(LayoutReplaced::node()); }
+private:
+};

Libraries/LibHTML/Layout/LayoutInline.cpp

@@ -4,6 +4,7 @@
 LayoutInline::LayoutInline(const Node& node, RefPtr<StyleProperties> style_properties)
     : LayoutNode(&node, move(style_properties))
 {
+    set_inline(true);
 }
 
 LayoutInline::~LayoutInline()

Libraries/LibHTML/Layout/LayoutInline.h

@@ -10,7 +10,6 @@ public:
     virtual ~LayoutInline() override;
 
     virtual const char* class_name() const override { return "LayoutInline"; }
-    virtual bool is_inline() const override { return true; }
 
     virtual void split_into_lines(LayoutBlock& container);
 

Libraries/LibHTML/Layout/LayoutNode.h

@@ -53,7 +53,9 @@ public:
     virtual const char* class_name() const { return "LayoutNode"; }
     virtual bool is_text() const { return false; }
     virtual bool is_block() const { return false; }
-    virtual bool is_inline() const { return false; }
+
+    bool is_inline() const { return m_inline; }
+    void set_inline(bool b) { m_inline = b; }
 
     virtual void layout();
     virtual void render(RenderingContext&);
@@ -81,4 +83,5 @@ private:
     RefPtr<StyleProperties> m_style_properties;
     BoxModelMetrics m_style;
     Rect m_rect;
+    bool m_inline { false };
 };

Libraries/LibHTML/Layout/LayoutReplaced.cpp

@@ -0,0 +1,13 @@
+#include <LibHTML/DOM/Element.h>
+#include <LibHTML/Layout/LayoutReplaced.h>
+
+LayoutReplaced::LayoutReplaced(const Element& element, NonnullRefPtr<StyleProperties> style)
+    : LayoutNode(&element, move(style))
+{
+    // FIXME: Allow non-inline replaced elements.
+    set_inline(true);
+}
+
+LayoutReplaced::~LayoutReplaced()
+{
+}

Libraries/LibHTML/Layout/LayoutReplaced.h

@@ -0,0 +1,12 @@
+#include <LibHTML/DOM/Element.h>
+#include <LibHTML/Layout/LayoutNode.h>
+
+class LayoutReplaced : public LayoutNode {
+public:
+    LayoutReplaced(const Element&, NonnullRefPtr<StyleProperties>);
+    virtual ~LayoutReplaced();
+
+    const Element& node() const { return static_cast<const Element&>(*LayoutNode::node()); }
+
+private:
+};