LibWeb: Avoid unnecessary Vector copying when generating line boxes

Carry the same Vector<Gfx::DrawGlyphOrEmoji> all the way from the inline
level iterator to the final line box fragment.

Userland/Libraries/LibWeb/Layout/InlineFormattingContext.cpp

@@ -348,7 +348,7 @@ void InlineFormattingContext::generate_line_boxes(LayoutMode layout_mode)
                 item.margin_end,
                 item.width,
                 text_node.computed_values().line_height(),
-                item.glyph_run);
+                move(item.glyph_run));
             break;
         }
         }

Userland/Libraries/LibWeb/Layout/LineBox.cpp

@@ -15,7 +15,7 @@
 
 namespace Web::Layout {
 
-void LineBox::add_fragment(Node const& layout_node, int start, int length, CSSPixels leading_size, CSSPixels trailing_size, CSSPixels leading_margin, CSSPixels trailing_margin, CSSPixels content_width, CSSPixels content_height, CSSPixels border_box_top, CSSPixels border_box_bottom, Span<Gfx::DrawGlyphOrEmoji const> glyph_run)
+void LineBox::add_fragment(Node const& layout_node, int start, int length, CSSPixels leading_size, CSSPixels trailing_size, CSSPixels leading_margin, CSSPixels trailing_margin, CSSPixels content_width, CSSPixels content_height, CSSPixels border_box_top, CSSPixels border_box_bottom, Vector<Gfx::DrawGlyphOrEmoji> glyph_run)
 {
     bool text_align_is_justify = layout_node.computed_values().text_align() == CSS::TextAlign::Justify;
     if (!text_align_is_justify && !m_fragments.is_empty() && &m_fragments.last().layout_node() == &layout_node) {
@@ -24,15 +24,14 @@ void LineBox::add_fragment(Node const& layout_node, int start, int length, CSSPi
         // Expand the last fragment instead of adding a new one with the same Layout::Node.
         m_fragments.last().m_length = (start - m_fragments.last().m_start) + length;
         m_fragments.last().set_width(m_fragments.last().width() + content_width);
-        for (auto glyph : glyph_run) {
+        for (auto& glyph : glyph_run) {
             glyph.visit([&](auto& glyph) { glyph.position.translate_by(fragment_width.to_float(), 0); });
             m_fragments.last().m_glyph_run->append(glyph);
         }
     } else {
-        Vector<Gfx::DrawGlyphOrEmoji> glyph_run_copy { glyph_run };
         CSSPixels x_offset = leading_margin + leading_size + m_width;
         CSSPixels y_offset = 0;
-        m_fragments.append(LineBoxFragment { layout_node, start, length, CSSPixelPoint(x_offset, y_offset), CSSPixelSize(content_width, content_height), border_box_top, move(glyph_run_copy) });
+        m_fragments.append(LineBoxFragment { layout_node, start, length, CSSPixelPoint(x_offset, y_offset), CSSPixelSize(content_width, content_height), border_box_top, move(glyph_run) });
     }
     m_width += leading_margin + leading_size + content_width + trailing_size + trailing_margin;
     m_height = max(m_height, content_height + border_box_top + border_box_bottom);

Userland/Libraries/LibWeb/Layout/LineBox.h

@@ -20,7 +20,7 @@ public:
     CSSPixels bottom() const { return m_bottom; }
     CSSPixels baseline() const { return m_baseline; }
 
-    void add_fragment(Node const& layout_node, int start, int length, CSSPixels leading_size, CSSPixels trailing_size, CSSPixels leading_margin, CSSPixels trailing_margin, CSSPixels content_width, CSSPixels content_height, CSSPixels border_box_top, CSSPixels border_box_bottom, Span<Gfx::DrawGlyphOrEmoji const> = {});
+    void add_fragment(Node const& layout_node, int start, int length, CSSPixels leading_size, CSSPixels trailing_size, CSSPixels leading_margin, CSSPixels trailing_margin, CSSPixels content_width, CSSPixels content_height, CSSPixels border_box_top, CSSPixels border_box_bottom, Vector<Gfx::DrawGlyphOrEmoji> = {});
 
     Vector<LineBoxFragment> const& fragments() const { return m_fragments; }
     Vector<LineBoxFragment>& fragments() { return m_fragments; }

Userland/Libraries/LibWeb/Layout/LineBuilder.cpp

@@ -97,9 +97,9 @@ void LineBuilder::append_box(Box const& box, CSSPixels leading_size, CSSPixels t
     };
 }
 
-void LineBuilder::append_text_chunk(TextNode const& text_node, size_t offset_in_node, size_t length_in_node, CSSPixels leading_size, CSSPixels trailing_size, CSSPixels leading_margin, CSSPixels trailing_margin, CSSPixels content_width, CSSPixels content_height, Span<Gfx::DrawGlyphOrEmoji> glyph_run)
+void LineBuilder::append_text_chunk(TextNode const& text_node, size_t offset_in_node, size_t length_in_node, CSSPixels leading_size, CSSPixels trailing_size, CSSPixels leading_margin, CSSPixels trailing_margin, CSSPixels content_width, CSSPixels content_height, Vector<Gfx::DrawGlyphOrEmoji> glyph_run)
 {
-    ensure_last_line_box().add_fragment(text_node, offset_in_node, length_in_node, leading_size, trailing_size, leading_margin, trailing_margin, content_width, content_height, 0, 0, glyph_run);
+    ensure_last_line_box().add_fragment(text_node, offset_in_node, length_in_node, leading_size, trailing_size, leading_margin, trailing_margin, content_width, content_height, 0, 0, move(glyph_run));
     m_max_height_on_current_line = max(m_max_height_on_current_line, content_height);
 }
 

Userland/Libraries/LibWeb/Layout/LineBuilder.h

@@ -25,7 +25,7 @@ public:
 
     void break_line(ForcedBreak, Optional<CSSPixels> next_item_width = {});
     void append_box(Box const&, CSSPixels leading_size, CSSPixels trailing_size, CSSPixels leading_margin, CSSPixels trailing_margin);
-    void append_text_chunk(TextNode const&, size_t offset_in_node, size_t length_in_node, CSSPixels leading_size, CSSPixels trailing_size, CSSPixels leading_margin, CSSPixels trailing_margin, CSSPixels content_width, CSSPixels content_height, Span<Gfx::DrawGlyphOrEmoji>);
+    void append_text_chunk(TextNode const&, size_t offset_in_node, size_t length_in_node, CSSPixels leading_size, CSSPixels trailing_size, CSSPixels leading_margin, CSSPixels trailing_margin, CSSPixels content_width, CSSPixels content_height, Vector<Gfx::DrawGlyphOrEmoji>);
 
     // Returns whether a line break occurred.
     bool break_if_needed(CSSPixels next_item_width)