Backed out changeset 8da43c1bdd49 (bug 1759891) causing Webrender busatges. CLOSED TREE

[ghsync] From https://hg.mozilla.org/mozilla-central/rev/73cf808ebf54ed0219d272128d7e459fc2dee5b1

Author: Butkovits Atila

webrender/src/glyph_rasterizer/mod.rs

@@ -549,7 +549,6 @@ struct MappedFontKey {
 }
 
 struct FontKeyMapLocked {
-    namespace: IdNamespace,
     next_id: u32,
     template_map: FastHashMap<FontTemplate, Arc<MappedFontKey>>,
     key_map: FastHashMap<FontKey, Arc<MappedFontKey>>,
@@ -562,15 +561,15 @@ struct FontKeyMapLocked {
 /// final shared key. The shared key will stay alive so long as there are
 /// any strong references to the mapping entry. Care must be taken when
 /// clearing namespaces of shared keys as this may trigger shared font keys
-/// to expire which require individual processing. Shared font keys will be
-/// created within the provided unique namespace.
+/// to expire which require individual processing.
 #[derive(Clone)]
 pub struct FontKeyMap(Arc<RwLock<FontKeyMapLocked>>);
 
 impl FontKeyMap {
-    pub fn new(namespace: IdNamespace) -> Self {
+    const SHARED_NAMESPACE: IdNamespace = IdNamespace(0);
+
+    pub fn new() -> Self {
         FontKeyMap(Arc::new(RwLock::new(FontKeyMapLocked {
-            namespace,
             next_id: 1,
             template_map: FastHashMap::default(),
             key_map: FastHashMap::default(),
@@ -601,7 +600,7 @@ impl FontKeyMap {
             locked.key_map.insert(*font_key, mapped);
             return None;
         }
-        let shared_key = FontKey::new(locked.namespace, locked.next_id);
+        let shared_key = FontKey::new(Self::SHARED_NAMESPACE, locked.next_id);
         locked.next_id += 1;
         let mapped = Arc::new(MappedFontKey {
             font_key: shared_key,
@@ -718,7 +717,6 @@ impl FontTemplateMap {
 }
 
 struct FontInstanceKeyMapLocked {
-    namespace: IdNamespace,
     next_id: u32,
     instances: FastHashSet<Arc<BaseFontInstance>>,
     key_map: FastHashMap<FontInstanceKey, Weak<BaseFontInstance>>,
@@ -731,15 +729,15 @@ struct FontInstanceKeyMapLocked {
 /// key to assign to that instance. When the weak count of the mapping is zero,
 /// the entry is allowed to expire. Again, care must be taken when clearing
 /// a namespace within the key map as it may cause shared key expirations that
-/// require individual processing. Shared instance keys will be created within
-/// the provided unique namespace.
+/// require individual processing.
 #[derive(Clone)]
 pub struct FontInstanceKeyMap(Arc<RwLock<FontInstanceKeyMapLocked>>);
 
 impl FontInstanceKeyMap {
-    pub fn new(namespace: IdNamespace) -> Self {
+    const SHARED_NAMESPACE: IdNamespace = IdNamespace(0);
+
+    pub fn new() -> Self {
         FontInstanceKeyMap(Arc::new(RwLock::new(FontInstanceKeyMapLocked {
-            namespace,
             next_id: 1,
             instances: FastHashSet::default(),
             key_map: FastHashMap::default(),
@@ -771,7 +769,7 @@ impl FontInstanceKeyMap {
             return None;
         }
         let unmapped_key = instance.instance_key;
-        instance.instance_key = FontInstanceKey::new(locked.namespace, locked.next_id);
+        instance.instance_key = FontInstanceKey::new(Self::SHARED_NAMESPACE, locked.next_id);
         locked.next_id += 1;
         let shared_instance = Arc::new(instance);
         locked.instances.insert(shared_instance.clone());
@@ -913,12 +911,12 @@ pub struct SharedFontResources {
 }
 
 impl SharedFontResources {
-    pub fn new(namespace: IdNamespace) -> Self {
+    pub fn new() -> Self {
         SharedFontResources {
             templates: FontTemplateMap::new(),
             instances: FontInstanceMap::new(),
-            font_keys: FontKeyMap::new(namespace),
-            instance_keys: FontInstanceKeyMap::new(namespace),
+            font_keys: FontKeyMap::new(),
+            instance_keys: FontInstanceKeyMap::new(),
         }
     }
 }

webrender/src/render_backend.rs

@@ -733,7 +733,7 @@ impl RenderBackend {
         }
     }
 
-    pub fn next_namespace_id() -> IdNamespace {
+    fn next_namespace_id(&self) -> IdNamespace {
         IdNamespace(NEXT_NAMESPACE_ID.fetch_add(1, Ordering::Relaxed) as u32)
     }
 
@@ -908,7 +908,7 @@ impl RenderBackend {
         match msg {
             ApiMsg::CloneApi(sender) => {
                 assert!(!self.namespace_alloc_by_client);
-                sender.send(Self::next_namespace_id()).unwrap();
+                sender.send(self.next_namespace_id()).unwrap();
             }
             ApiMsg::CloneApiByClient(namespace_id) => {
                 assert!(self.namespace_alloc_by_client);

webrender/src/renderer/mod.rs

@@ -1212,9 +1212,7 @@ impl Renderer {
         let sampler = options.sampler;
         let namespace_alloc_by_client = options.namespace_alloc_by_client;
 
-        // Ensure shared font keys exist within their own unique namespace so
-        // that they don't accidentally collide across Renderer instances.
-        let fonts = SharedFontResources::new(RenderBackend::next_namespace_id());
+        let fonts = SharedFontResources::new();
 
         let blob_image_handler = options.blob_image_handler.take();
         let scene_builder_hooks = options.scene_builder_hooks;