LibHTML: Implement LayoutInline::layout()

This currently uses a gross hack where it subtracts 11px from the
previous sibling bottom to calculate its top. This should be fixed
by switching to a proper two-phase line layouting model, were we
first distribute inline elements into lines and figure out their
horizontal positions and heights; then compute the needed line
heights and position inline elements there vertically.

Libraries/LibHTML/Layout/LayoutInline.cpp

@@ -9,3 +9,29 @@ LayoutInline::LayoutInline(const Node& node, StyleProperties&& style_properties)
 LayoutInline::~LayoutInline()
 {
 }
+
+void LayoutInline::layout()
+{
+    Point origin;
+
+    if (previous_sibling() != nullptr) {
+        auto& previous_sibling_rect = previous_sibling()->rect();
+        auto& previous_sibling_style = previous_sibling()->style();
+        origin = previous_sibling_rect.location();
+        // FIXME: Implement proper inline positioning when
+        // there are nodes with different heights. And don't
+        // hardcode font size like we do here.
+        origin.move_by(previous_sibling_rect.width(), previous_sibling_rect.height());
+        origin.move_by(previous_sibling_style.full_margin().right, -11);
+    } else {
+        origin = parent()->rect().location();
+    }
+
+    rect().set_location(origin);
+
+    for_each_child([&](auto& child) {
+        child.layout();
+        rect().set_right(child.rect().right() + child.style().full_margin().right);
+        rect().set_bottom(child.rect().bottom() + child.style().full_margin().bottom);
+    });
+}

Libraries/LibHTML/Layout/LayoutInline.h

@@ -12,5 +12,7 @@ public:
     virtual const char* class_name() const override { return "LayoutInline"; }
     virtual bool is_inline() const override { return true; }
 
+    virtual void layout() override;
+
 private:
 };