LibWeb: Use the new Gfx::Painter::draw_text_run() API for drawing text

This avoids a bunch of unnecessary work in Painter which not only took
time, but sometimes also led to alignment issues. draw_text_run() will
draw the text where we tell it, and that's it.

Userland/Libraries/LibWeb/Layout/LineBoxFragment.h

@@ -43,6 +43,10 @@ public:
     const Gfx::FloatPoint& offset() const { return m_offset; }
     void set_offset(const Gfx::FloatPoint& offset) { m_offset = offset; }
 
+    // The baseline of a fragment is the number of pixels from the top to the text baseline.
+    void set_baseline(float y) { m_baseline = y; }
+    float baseline() const { return m_baseline; }
+
     const Gfx::FloatSize& size() const { return m_size; }
     void set_width(float width) { m_size.set_width(width); }
     void set_height(float height) { m_size.set_height(height); }
@@ -75,6 +79,7 @@ private:
     Gfx::FloatSize m_size;
     float m_border_box_top { 0 };
     float m_border_box_bottom { 0 };
+    float m_baseline { 0 };
     Type m_type { Type::Normal };
 };