LibWeb: Make <canvas> use the generic replaced layout algorithm

LayoutCanvas now communicates intrinsic size to LayoutReplaced so it
can use the normal replaced algorithm.

Libraries/LibWeb/Layout/LayoutCanvas.cpp

@@ -42,8 +42,10 @@ LayoutCanvas::~LayoutCanvas()
 
 void LayoutCanvas::layout(LayoutMode layout_mode)
 {
-    rect().set_width(node().requested_width());
-    rect().set_height(node().requested_height());
+    set_has_intrinsic_width(true);
+    set_has_intrinsic_height(true);
+    set_intrinsic_width(node().requested_width());
+    set_intrinsic_height(node().requested_height());
     LayoutReplaced::layout(layout_mode);
 }