Apply overflow to replaced boxes

See:
- w3c/csswg-drafts#7058
- whatwg/html#8028

Author: liZe

weasyprint/css/html5_ua.css

@@ -543,6 +543,7 @@ style { display: none; }
 sub { font-size: smaller; line-height: normal; vertical-align: sub; }
 summary { display: block; /* unicode-bidi: isolate; */ }
 sup { font-size: smaller; line-height: normal; vertical-align: super; }
+img, svg { overflow: hidden; }
 
 table { border-collapse: separate; border-color: gray; border-spacing: 2px; display: table; text-indent: 0; /* unicode-bidi: isolate; */ }
 

weasyprint/css/tests_ua.css

@@ -34,6 +34,8 @@ h4 { bookmark-level: 4; bookmark-label: content(text) }
 h5 { bookmark-level: 5; bookmark-label: content(text) }
 h6 { bookmark-level: 6; bookmark-label: content(text) }
 
+img, svg { overflow: hidden; }
+
 ::marker { unicode-bidi: isolate; font-variant-numeric: tabular-nums }
 
 ::footnote-call { content: counter(footnote) }

weasyprint/draw.py

@@ -113,7 +113,7 @@ def draw_stacking_context(stream, stacking_context):
         # Point 2
         if isinstance(box, (boxes.BlockBox, boxes.MarginBox,
                             boxes.InlineBlockBox, boxes.TableCellBox,
-                            boxes.FlexContainerBox)):
+                            boxes.FlexContainerBox, boxes.ReplacedBox)):
             # The canvas background was removed by layout_backgrounds
             draw_background(stream, box.background)
             draw_border(stream, box)
@@ -148,14 +148,12 @@ def draw_stacking_context(stream, stacking_context):
             # Point 6
             if isinstance(box, boxes.InlineBox):
                 draw_inline_level(stream, stacking_context.page, box)
+            elif isinstance(box, boxes.ReplacedBox):
+                draw_replacedbox(stream, box)
 
             # Point 7
             for block in [box] + stacking_context.blocks_and_cells:
-                if isinstance(block, boxes.ReplacedBox):
-                    draw_background(stream, block.background)
-                    draw_border(stream, block)
-                    draw_replacedbox(stream, block)
-                elif block.children:
+                if block.children:
                     if block != box:
                         stream.begin_marked_content(block, mcid=True)
                     if isinstance(block.children[-1], boxes.LineBox):
@@ -983,9 +981,6 @@ def draw_replacedbox(stream, box):
         return
 
     with stacked(stream):
-        rounded_box_path(stream, box.rounded_content_box())
-        stream.clip()
-        stream.end()
         stream.transform(e=draw_x, f=draw_y)
         with stacked(stream):
             # TODO: Use the real intrinsic size here, not affected by