LibWeb: Verify each sample corners command has matching blit command

Userland/Libraries/LibWeb/Painting/BorderRadiusCornerClipper.cpp

@@ -135,7 +135,7 @@ ScopedCornerRadiusClip::~ScopedCornerRadiusClip()
 {
     if (!m_has_radius)
         return;
-    m_context.recording_painter().blit_corner_clipping(m_id, m_border_rect);
+    m_context.recording_painter().blit_corner_clipping(m_id);
 }
 
 }

Userland/Libraries/LibWeb/Painting/PaintableBox.cpp

@@ -499,7 +499,6 @@ void PaintableBox::clear_clip_overflow_rect(PaintContext& context, PaintPhase ph
 
     if (m_clipping_overflow) {
         m_clipping_overflow = false;
-        auto const& combined_transform = combined_css_transform();
         auto const& border_radii_clips = this->border_radii_clips();
         for (int corner_clip_index = border_radii_clips.size() - 1; corner_clip_index >= 0; --corner_clip_index) {
             auto const& corner_clip = border_radii_clips[corner_clip_index];
@@ -508,8 +507,7 @@ void PaintableBox::clear_clip_overflow_rect(PaintContext& context, PaintPhase ph
                 continue;
             auto corner_clipper_id = m_corner_clipper_ids[corner_clip_index];
             m_corner_clipper_ids[corner_clip_index] = corner_clipper_id;
-            auto rect = corner_clip.rect.translated(-combined_transform.translation().to_type<CSSPixels>());
-            context.recording_painter().blit_corner_clipping(corner_clipper_id, context.rounded_device_rect(rect).to_type<int>());
+            context.recording_painter().blit_corner_clipping(corner_clipper_id);
         }
         context.recording_painter().restore();
     }
@@ -724,7 +722,7 @@ void PaintableWithLines::paint(PaintContext& context, PaintPhase phase) const
     if (should_clip_overflow) {
         context.recording_painter().restore();
         if (corner_clip_id.has_value()) {
-            context.recording_painter().blit_corner_clipping(*corner_clip_id, context.rounded_device_rect(clip_box).to_type<int>());
+            context.recording_painter().blit_corner_clipping(*corner_clip_id);
             corner_clip_id = {};
         }
         context.recording_painter().restore();

Userland/Libraries/LibWeb/Painting/RecordingPainter.cpp

@@ -15,6 +15,11 @@ RecordingPainter::RecordingPainter(CommandList& command_list)
     m_state_stack.append(State());
 }
 
+RecordingPainter::~RecordingPainter()
+{
+    VERIFY(m_corner_clip_state_stack.is_empty());
+}
+
 void RecordingPainter::append(Command&& command)
 {
     m_command_list.append(move(command), state().scroll_frame_id);
@@ -22,6 +27,7 @@ void RecordingPainter::append(Command&& command)
 
 void RecordingPainter::sample_under_corners(u32 id, CornerRadii corner_radii, Gfx::IntRect border_rect, CornerClip corner_clip)
 {
+    m_corner_clip_state_stack.append({ id, border_rect });
     append(SampleUnderCorners {
         id,
         corner_radii,
@@ -29,9 +35,11 @@ void RecordingPainter::sample_under_corners(u32 id, CornerRadii corner_radii, Gf
         corner_clip });
 }
 
-void RecordingPainter::blit_corner_clipping(u32 id, Gfx::IntRect border_rect)
+void RecordingPainter::blit_corner_clipping(u32 id)
 {
-    append(BlitCornerClipping { id, border_rect = state().translation.map(border_rect) });
+    auto clip_state = m_corner_clip_state_stack.take_last();
+    VERIFY(clip_state.id == id);
+    append(BlitCornerClipping { id, state().translation.map(clip_state.rect) });
 }
 
 void RecordingPainter::fill_rect(Gfx::IntRect const& rect, Color color, Vector<Gfx::Path> const& clip_paths)

Userland/Libraries/LibWeb/Painting/RecordingPainter.h

@@ -127,7 +127,7 @@ public:
     void pop_stacking_context();
 
     void sample_under_corners(u32 id, CornerRadii corner_radii, Gfx::IntRect border_rect, CornerClip corner_clip);
-    void blit_corner_clipping(u32 id, Gfx::IntRect border_rect);
+    void blit_corner_clipping(u32 id);
 
     void apply_backdrop_filter(Gfx::IntRect const& backdrop_region, BorderRadiiData const& border_radii_data, CSS::ResolvedBackdropFilter const& backdrop_filter);
 
@@ -144,6 +144,7 @@ public:
     void paint_borders(DevicePixelRect const& border_rect, CornerRadii const& corner_radii, BordersDataDevicePixels const& borders_data);
 
     RecordingPainter(CommandList& commands_list);
+    ~RecordingPainter();
 
     CommandList& commands_list() { return m_command_list; }
 
@@ -158,6 +159,12 @@ private:
     State& state() { return m_state_stack.last(); }
     State const& state() const { return m_state_stack.last(); }
 
+    struct CornerClipState {
+        u32 id;
+        Gfx::IntRect rect;
+    };
+    Vector<CornerClipState> m_corner_clip_state_stack;
+
     Vector<State> m_state_stack;
     CommandList& m_command_list;
 };