Various memory measurement improvements (#36834)

The two significant changes here are 1) a commit that frees memory used
to perform memory reporting once the reporting is complete, 2) memory
reporting for the system font service. There are various other commits
that remove `#[ignore_malloc_size_of]` attributes for data that we are
now able to measure, but they do not significantly change our
measurements when testing servo.org.

Testing: Comparing the output of about:memory on servo.org.

---------

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

1 files changed, 2 insertions, 7 deletions

diff --git a/components/layout/layout_impl.rs b/components/layout/layout_impl.rs
index b8d91c38027..cdf76d3fed0 100644
--- a/components/layout/layout_impl.rs
+++ b/components/layout/layout_impl.rs
@@ -4,9 +4,8 @@
 
 #![allow(unsafe_code)]
 
-use std::cell::{Cell, LazyCell, RefCell};
-use std::collections::{HashMap, HashSet};
-use std::ffi::c_void;
+use std::cell::{Cell, RefCell};
+use std::collections::HashMap;
 use std::fmt::Debug;
 use std::process;
 use std::sync::{Arc, LazyLock};
@@ -95,10 +94,6 @@ use crate::{BoxTree, FragmentTree};
 static STYLE_THREAD_POOL: Mutex<&style::global_style_data::STYLE_THREAD_POOL> =
     Mutex::new(&style::global_style_data::STYLE_THREAD_POOL);
 
-thread_local!(static SEEN_POINTERS: LazyCell<RefCell<HashSet<*const c_void>>> = const {
-    LazyCell::new(|| RefCell::new(HashSet::new()))
-});
-
 /// A CSS file to style the user agent stylesheet.
 static USER_AGENT_CSS: &[u8] = include_bytes!("./stylesheets/user-agent.css");