gfx: Remove `FontTemplateData` (#32034)

Now that `FontTemplateData` is more or less the same on all platforms,
it can be removed. This is a preparatory change for a full refactor of
the font system on Servo. The major changes here are:

 - Remove `FontTemplateData` and move its members into `FontTemplate`
 - Make `FontTemplate` have full interior mutability instead of only
   the `FontTemplateData` member. This is preparation for having these
   data types `Send` and `Sync` with locking.
 - Remove the strong/weak reference concept for font data. In practice,
   all font data references were strong, so this was never fully
   complete. Instead of using this approach, the new font system will
   use a central font data cache with references associated to layouts.
 - The `CTFont` cache is now a global cache, so `CTFont`s can be shared
   between threads. The cache is cleared when clearing font caches.

A benefit of this change (apart from `CTFont` sharing) is that font data
loading is platform-independent now.

1 files changed, 4 insertions, 3 deletions

diff --git a/components/gfx/text/text_run.rs b/components/gfx/text/text_run.rs
index a411c7125db..56f66d6cd1f 100644
--- a/components/gfx/text/text_run.rs
+++ b/components/gfx/text/text_run.rs
@@ -17,7 +17,7 @@ use webrender_api::FontInstanceKey;
 use xi_unicode::LineBreakLeafIter;
 
 use crate::font::{Font, FontHandleMethods, FontMetrics, RunMetrics, ShapingFlags, ShapingOptions};
-use crate::platform::font_template::FontTemplateData;
+use crate::font_template::FontTemplateRefMethods;
 use crate::text::glyph::{ByteIndex, GlyphStore};
 
 thread_local! {
@@ -30,7 +30,8 @@ thread_local! {
 pub struct TextRun {
     /// The UTF-8 string represented by this text run.
     pub text: Arc<String>,
-    pub font_template: Arc<FontTemplateData>,
+    /// This ensures the data stays alive as long as this TextRun is using this font.
+    font_data: Arc<Vec<u8>>,
     pub pt_size: Au,
     pub font_metrics: FontMetrics,
     pub font_key: FontInstanceKey,
@@ -193,7 +194,7 @@ impl<'a> TextRun {
             TextRun {
                 text: Arc::new(text),
                 font_metrics: font.metrics.clone(),
-                font_template: font.handle.template(),
+                font_data: font.handle.template().data(),
                 font_key: font.font_key,
                 pt_size: font.descriptor.pt_size,
                 glyphs: Arc::new(glyphs),