script: add skeleton implementation of FontFace API (#35262)

This patch implements the `FontFace` interface, but with some caveats

1. The interface is only exposed on `Window`. Support for Workers will
   be handled in the future.
2. The concept of `css-connected` `FontFace` is not implemented, so
   `@font-face` rules in stylesheets will not be represented in the DOM.
3. The constructor only supports using `url()` strings as source
   and `ArrayBuffer` and `ArrayBufferView` are not supported yet.

A skeleton implementation of the `load` method of `FontFaceSet` is also
implemented in this patch. The intention is to support some web pages
that don't load without this method.

Signed-off-by: Mukilan Thiyagarajan <mukilan@igalia.com>

components/shared/background_hang_monitor/lib.rs

@@ -21,6 +21,7 @@ pub enum ScriptHangAnnotation {
     DevtoolsMsg,
     DocumentEvent,
     FileRead,
+    FontLoading,
     FormPlannedNavigation,
     ImageCacheMsg,
     InputEvent,

components/shared/fonts/lib.rs

@@ -17,4 +17,4 @@ int_range_index! {
     struct ByteIndex(isize)
 }
 
-pub type WebFontLoadFinishedCallback = Arc<dyn Fn(bool) + Send + Sync + 'static>;
+pub type StylesheetWebFontLoadFinishedCallback = Arc<dyn Fn(bool) + Send + Sync + 'static>;

components/shared/net/lib.rs

@@ -524,7 +524,7 @@ enum ToFetchThreadMessage {
     FetchResponse(FetchResponseMsg),
 }
 
-pub type BoxedFetchCallback = Box<dyn Fn(FetchResponseMsg) + Send + 'static>;
+pub type BoxedFetchCallback = Box<dyn FnMut(FetchResponseMsg) + Send + 'static>;
 
 /// A thread to handle fetches in a Servo process. This thread is responsible for
 /// listening for new fetch requests as well as updates on those operations and forwarding
@@ -601,7 +601,7 @@ impl FetchThread {
                         matches!(fetch_response_msg, FetchResponseMsg::ProcessResponseEOF(..));
 
                     self.active_fetches
-                        .get(&request_id)
+                        .get_mut(&request_id)
                         .expect("Got fetch response for unknown fetch")(
                         fetch_response_msg
                     );

components/shared/profile/time.rs

@@ -90,43 +90,44 @@ pub enum ProfilerCategory {
 
     ScriptEvent = 0x66,
     ScriptFileRead = 0x67,
-    ScriptImageCacheMsg = 0x68,
-    ScriptInputEvent = 0x69,
-    ScriptNetworkEvent = 0x6a,
+    ScriptFontLoading = 0x68,
+    ScriptImageCacheMsg = 0x69,
+    ScriptInputEvent = 0x6a,
+    ScriptNetworkEvent = 0x6b,
 
     /// The script thread is parsing HTML, rather than doing other work like evaluating scripts or doing layout.
-    ScriptParseHTML = 0x6b,
+    ScriptParseHTML = 0x6c,
 
-    ScriptPlannedNavigation = 0x6c,
-    ScriptResize = 0x6d,
-    ScriptRendering = 0x6e,
-    ScriptSetScrollState = 0x6f,
-    ScriptSetViewport = 0x70,
-    ScriptTimerEvent = 0x71,
-    ScriptStylesheetLoad = 0x72,
-    ScriptUpdateReplacedElement = 0x73,
-    ScriptWebSocketEvent = 0x74,
-    ScriptWorkerEvent = 0x75,
-    ScriptServiceWorkerEvent = 0x76,
+    ScriptPlannedNavigation = 0x6d,
+    ScriptResize = 0x6e,
+    ScriptRendering = 0x6f,
+    ScriptSetScrollState = 0x70,
+    ScriptSetViewport = 0x71,
+    ScriptTimerEvent = 0x72,
+    ScriptStylesheetLoad = 0x73,
+    ScriptUpdateReplacedElement = 0x74,
+    ScriptWebSocketEvent = 0x75,
+    ScriptWorkerEvent = 0x76,
+    ScriptServiceWorkerEvent = 0x77,
 
     /// The script thread is parsing XML, rather than doing other work like evaluating scripts or doing layout.
-    ScriptParseXML = 0x77,
+    ScriptParseXML = 0x78,
 
-    ScriptEnterFullscreen = 0x78,
-    ScriptExitFullscreen = 0x79,
-    ScriptWorkletEvent = 0x7a,
-    ScriptPerformanceEvent = 0x7b,
-    ScriptHistoryEvent = 0x7c,
-    ScriptPortMessage = 0x7d,
-    ScriptWebGPUMsg = 0x7e,
+    ScriptEnterFullscreen = 0x79,
+    ScriptExitFullscreen = 0x7a,
+    ScriptWorkletEvent = 0x7b,
+    ScriptPerformanceEvent = 0x7c,
+    ScriptHistoryEvent = 0x7d,
+    ScriptPortMessage = 0x7e,
+    ScriptWebGPUMsg = 0x7f,
 
     /// Web performance metrics.
-    TimeToFirstPaint = 0x80,
-    TimeToFirstContentfulPaint = 0x81,
-    TimeToInteractive = 0x82,
+    TimeToFirstPaint = 0x90,
+    TimeToFirstContentfulPaint = 0x91,
+    TimeToInteractive = 0x92,
 
-    IpcReceiver = 0x83,
-    IpcBytesReceiver = 0x84,
+    IpcReceiver = 0x93,
+    IpcBytesReceiver = 0x94,
 }
 
 impl ProfilerCategory {
@@ -151,6 +152,7 @@ impl ProfilerCategory {
             ProfilerCategory::ScriptEvaluate => "ScriptEvaluate",
             ProfilerCategory::ScriptEvent => "ScriptEvent",
             ProfilerCategory::ScriptFileRead => "ScriptFileRead",
+            ProfilerCategory::ScriptFontLoading => "ScriptFontLoading",
             ProfilerCategory::ScriptImageCacheMsg => "ScriptImageCacheMsg",
             ProfilerCategory::ScriptInputEvent => "ScriptInputEvent",
             ProfilerCategory::ScriptNetworkEvent => "ScriptNetworkEvent",