LibWeb: Pass PaintingSurface into DisplayListPlayer::execute()

Deleteing set_surface() makes DisplayListPlayer API a bit more intuitive
because now caller doesn't have to think whether it's necessary to
restore previous surface after execution, instead DisplayListPlayer
takes care of it by maintaining a stack of surfaces.

Libraries/LibWeb/CSS/StyleValues/CursorStyleValue.cpp

@@ -94,8 +94,7 @@ Optional<Gfx::ImageCursor> CursorStyleValue::make_image_cursor(Layout::NodeWithS
         case DisplayListPlayerType::SkiaCPU: {
             auto painting_surface = Gfx::PaintingSurface::wrap_bitmap(bitmap);
             Painting::DisplayListPlayerSkia display_list_player;
-            display_list_player.set_surface(painting_surface);
-            display_list_player.execute(*display_list);
+            display_list_player.execute(*display_list, painting_surface);
             break;
         }
         }

Libraries/LibWeb/HTML/RenderingThread.cpp

@@ -49,8 +49,7 @@ void RenderingThread::rendering_thread_loop()
             break;
         }
 
-        m_skia_player->set_surface(task->painting_surface);
-        m_skia_player->execute(*task->display_list);
+        m_skia_player->execute(*task->display_list, task->painting_surface);
         m_main_thread_event_loop.deferred_invoke([callback = move(task->callback)] {
             callback();
         });

Libraries/LibWeb/Painting/DisplayList.cpp

@@ -35,13 +35,20 @@ static bool command_is_clip_or_mask(Command const& command)
         });
 }
 
-void DisplayListPlayer::execute(DisplayList& display_list)
+void DisplayListPlayer::execute(DisplayList& display_list, RefPtr<Gfx::PaintingSurface> surface)
 {
+    if (surface)
+        m_surfaces.append(*surface);
+    ScopeGuard guard = [&surfaces = m_surfaces, pop_surface_from_stack = !!surface] {
+        if (pop_surface_from_stack)
+            (void)surfaces.take_last();
+    };
+
     auto const& commands = display_list.commands();
     auto const& scroll_state = display_list.scroll_state();
     auto device_pixels_per_css_pixel = display_list.device_pixels_per_css_pixel();
 
-    VERIFY(m_surface);
+    VERIFY(!m_surfaces.is_empty());
 
     for (size_t command_index = 0; command_index < commands.size(); command_index++) {
         auto scroll_frame_id = commands[command_index].scroll_frame_id;

Libraries/LibWeb/Painting/DisplayList.h

@@ -26,11 +26,10 @@ class DisplayListPlayer {
 public:
     virtual ~DisplayListPlayer() = default;
 
-    void execute(DisplayList&);
-    void set_surface(NonnullRefPtr<Gfx::PaintingSurface> surface) { m_surface = surface; }
+    void execute(DisplayList&, RefPtr<Gfx::PaintingSurface>);
 
 protected:
-    Gfx::PaintingSurface& surface() const { return *m_surface; }
+    Gfx::PaintingSurface& surface() const { return m_surfaces.last(); }
 
 private:
     virtual void flush() = 0;
@@ -74,7 +73,7 @@ private:
     virtual void apply_mask_bitmap(ApplyMaskBitmap const&) = 0;
     virtual bool would_be_fully_clipped_by_painter(Gfx::IntRect) const = 0;
 
-    RefPtr<Gfx::PaintingSurface> m_surface;
+    Vector<NonnullRefPtr<Gfx::PaintingSurface>, 1> m_surfaces;
 };
 
 class DisplayList : public AtomicRefCounted<DisplayList> {

Libraries/LibWeb/Painting/DisplayListPlayerSkia.cpp

@@ -972,10 +972,7 @@ void DisplayListPlayerSkia::add_mask(AddMask const& command)
 
     auto mask_surface = Gfx::PaintingSurface::create_with_size(m_context, rect.size(), Gfx::BitmapFormat::BGRA8888, Gfx::AlphaType::Premultiplied);
 
-    NonnullRefPtr old_surface = surface();
-    set_surface(mask_surface);
-    execute(*command.display_list);
-    set_surface(old_surface);
+    execute(*command.display_list, mask_surface);
 
     SkMatrix mask_matrix;
     mask_matrix.setTranslate(rect.x(), rect.y());
@@ -988,7 +985,7 @@ void DisplayListPlayerSkia::paint_nested_display_list(PaintNestedDisplayList con
 {
     auto& canvas = surface().canvas();
     canvas.translate(command.rect.x(), command.rect.y());
-    execute(*command.display_list);
+    execute(*command.display_list, {});
 }
 
 void DisplayListPlayerSkia::paint_scrollbar(PaintScrollBar const& command)

Libraries/LibWeb/Painting/SVGMaskable.cpp

@@ -100,8 +100,7 @@ RefPtr<Gfx::ImmutableBitmap> SVGMaskable::calculate_mask_of_svg(PaintContext& co
         StackingContext::paint_svg(paint_context, paintable, PaintPhase::Foreground);
         auto painting_surface = Gfx::PaintingSurface::wrap_bitmap(*mask_bitmap);
         DisplayListPlayerSkia display_list_player;
-        display_list_player.set_surface(painting_surface);
-        display_list_player.execute(display_list);
+        display_list_player.execute(display_list, painting_surface);
         return mask_bitmap;
     };
     RefPtr<Gfx::Bitmap> mask_bitmap = {};

Libraries/LibWeb/SVG/SVGDecodedImageData.cpp

@@ -106,8 +106,7 @@ RefPtr<Gfx::Bitmap> SVGDecodedImageData::render(Gfx::IntSize size) const
     case DisplayListPlayerType::SkiaCPU: {
         auto painting_surface = Gfx::PaintingSurface::wrap_bitmap(*bitmap);
         Painting::DisplayListPlayerSkia display_list_player;
-        display_list_player.set_surface(painting_surface);
-        display_list_player.execute(*display_list);
+        display_list_player.execute(*display_list, painting_surface);
         break;
     }
     default: