LibWeb: Implement Resource Timing

Author: https://github.com/Lubrsi
Commit: 6d1f78198d
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/3704
Reviewed-by: https://github.com/ADKaster ✅

Libraries/LibWeb/Forward.h

@@ -74,6 +74,7 @@ enum class MediaEncodingType : u8;
 enum class MediaKeysRequirement : u8;
 enum class ReadableStreamReaderMode : u8;
 enum class ReferrerPolicy : u8;
+enum class RenderBlockingStatusType : u8;
 enum class RequestCache : u8;
 enum class RequestCredentials : u8;
 enum class RequestDestination : u8;
@@ -756,6 +757,10 @@ namespace Web::ResizeObserver {
 class ResizeObserver;
 }
 
+namespace Web::ResourceTiming {
+class PerformanceResourceTiming;
+}
+
 namespace Web::Selection {
 class Selection;
 }