[Skrifa] Avoid initialization of HashSet with system random numbers

Workaround for [1] and [2] - issues in the Chrome sandbox requiring
access to random number generators.

[1] https://bugs.chromium.org/p/chromium/issues/detail?id=1516634
[2] https://bugs.chromium.org/p/chromium/issues/detail?id=1516641

skrifa/src/color/mod.rs

@@ -57,7 +57,9 @@ use read_fonts::{
 
 use std::{collections::HashSet, fmt::Debug, ops::Range};
 
-use traversal::{get_clipbox_font_units, traverse_v0_range, traverse_with_callbacks};
+use traversal::{
+    get_clipbox_font_units, traverse_v0_range, traverse_with_callbacks, NonRandomHasherState,
+};
 
 pub use transform::Transform;
 
@@ -322,7 +324,7 @@ impl<'a> ColorGlyph<'a> {
                     painter.push_clip_box(rect);
                 }
 
-                let mut visited_set: HashSet<usize> = HashSet::new();
+                let mut visited_set = HashSet::with_hasher(NonRandomHasherState {});
                 visited_set.insert(*paint_id);
                 traverse_with_callbacks(
                     &resolve_paint(&instance, paint)?,

skrifa/src/color/traversal.rs

@@ -1,4 +1,7 @@
-use std::{cmp::Ordering, collections::HashSet, ops::Range};
+use std::{
+    cmp::Ordering, collections::hash_map::DefaultHasher, collections::HashSet, hash::BuildHasher,
+    ops::Range,
+};
 
 use read_fonts::{
     tables::colr::{CompositeMode, Extend},
@@ -13,6 +16,16 @@ use super::{
     Brush, ColorPainter, ColorStop, PaintCachedColorGlyph, PaintError,
 };
 
+// Workaround for https://bugs.chromium.org/p/chromium/issues/detail?id=1516634.
+pub(crate) struct NonRandomHasherState;
+
+impl BuildHasher for NonRandomHasherState {
+    type Hasher = DefaultHasher;
+    fn build_hasher(&self) -> DefaultHasher {
+        DefaultHasher::new()
+    }
+}
+
 pub(crate) fn get_clipbox_font_units(
     colr_instance: &ColrInstance,
     glyph_id: GlyphId,
@@ -43,7 +56,7 @@ pub(crate) fn traverse_with_callbacks(
     paint: &ResolvedPaint,
     instance: &ColrInstance,
     painter: &mut impl ColorPainter,
-    visited_set: &mut HashSet<usize>,
+    visited_set: &mut HashSet<usize, NonRandomHasherState>,
 ) -> Result<(), PaintError> {
     match paint {
         ResolvedPaint::ColrLayers { range } => {