layout: Report memory usage for fragment and box trees. (#36553)

Add memory reporter integration for the fragment and box trees that are
persisted in the layout thread.

Testing: Looked at the numbers for https://servo.org and
https://html.spec.whatwg.org/. The former was very small, but the latter
was 700mb.

---------

Signed-off-by: Josh Matthews <josh@joshmatthews.net>

1 files changed, 7 insertions, 1 deletions

diff --git a/components/layout_2020/fragment_tree/box_fragment.rs b/components/layout_2020/fragment_tree/box_fragment.rs
index d0c96b3ea03..30be154caf1 100644
--- a/components/layout_2020/fragment_tree/box_fragment.rs
+++ b/components/layout_2020/fragment_tree/box_fragment.rs
@@ -5,6 +5,7 @@
 use app_units::Au;
 use atomic_refcell::AtomicRefCell;
 use base::print_tree::PrintTree;
+use malloc_size_of_derive::MallocSizeOf;
 use servo_arc::Arc as ServoArc;
 use style::Zero;
 use style::computed_values::border_collapse::T as BorderCollapse;
@@ -24,6 +25,7 @@ use crate::table::SpecificTableGridInfo;
 use crate::taffy::SpecificTaffyGridInfo;
 
 /// Describes how a [`BoxFragment`] paints its background.
+#[derive(MallocSizeOf)]
 pub(crate) enum BackgroundMode {
     /// Draw the normal [`BoxFragment`] background as well as the extra backgrounds
     /// based on the style and positioning rectangles in this data structure.
@@ -36,12 +38,14 @@ pub(crate) enum BackgroundMode {
     Normal,
 }
 
+#[derive(MallocSizeOf)]
 pub(crate) struct ExtraBackground {
+    #[conditional_malloc_size_of]
     pub style: ServoArc<ComputedValues>,
     pub rect: PhysicalRect<Au>,
 }
 
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, MallocSizeOf)]
 pub(crate) enum SpecificLayoutInfo {
     Grid(Box<SpecificTaffyGridInfo>),
     TableCellWithCollapsedBorders,
@@ -49,9 +53,11 @@ pub(crate) enum SpecificLayoutInfo {
     TableWrapper,
 }
 
+#[derive(MallocSizeOf)]
 pub(crate) struct BoxFragment {
     pub base: BaseFragment,
 
+    #[conditional_malloc_size_of]
     pub style: ServoArc<ComputedValues>,
     pub children: Vec<Fragment>,