LibWeb: Improve Enum generation in IDLGenerator

Generated enums have no underlying type specifier, this adds one
It uses the smallest available, which is mostly u8

Libraries/LibWeb/EncryptedMediaExtensions/EncryptedMediaExtensions.h

@@ -6,10 +6,12 @@
 
 #pragma once
 
+#include <AK/Types.h>
+
 namespace Web::Bindings {
 
 // https://w3c.github.io/encrypted-media/#dom-mediakeysrequirement
-enum class MediaKeysRequirement {
+enum class MediaKeysRequirement : u8 {
     Required,
     Optional,
     NotAllowed

Libraries/LibWeb/Forward.h

@@ -59,33 +59,33 @@ namespace Web::Bindings {
 class Intrinsics;
 class OptionConstructor;
 
-enum class AudioContextLatencyCategory;
-enum class CanPlayTypeResult;
-enum class CanvasFillRule;
-enum class CanvasTextAlign;
-enum class CanvasTextBaseline;
-enum class ColorGamut;
-enum class DOMParserSupportedType;
-enum class EndingType;
-enum class HdrMetadataType;
-enum class ImageSmoothingQuality;
-enum class MediaDecodingType;
-enum class MediaEncodingType;
-enum class MediaKeysRequirement;
-enum class ReadableStreamReaderMode;
-enum class ReferrerPolicy;
-enum class RequestCache;
-enum class RequestCredentials;
-enum class RequestDestination;
-enum class RequestDuplex;
-enum class RequestMode;
-enum class RequestPriority;
-enum class RequestRedirect;
-enum class ResizeObserverBoxOptions;
-enum class ResponseType;
-enum class TextTrackKind;
-enum class TransferFunction;
-enum class XMLHttpRequestResponseType;
+enum class AudioContextLatencyCategory : u8;
+enum class CanPlayTypeResult : u8;
+enum class CanvasFillRule : u8;
+enum class CanvasTextAlign : u8;
+enum class CanvasTextBaseline : u8;
+enum class ColorGamut : u8;
+enum class DOMParserSupportedType : u8;
+enum class EndingType : u8;
+enum class HdrMetadataType : u8;
+enum class ImageSmoothingQuality : u8;
+enum class MediaDecodingType : u8;
+enum class MediaEncodingType : u8;
+enum class MediaKeysRequirement : u8;
+enum class ReadableStreamReaderMode : u8;
+enum class ReferrerPolicy : u8;
+enum class RequestCache : u8;
+enum class RequestCredentials : u8;
+enum class RequestDestination : u8;
+enum class RequestDuplex : u8;
+enum class RequestMode : u8;
+enum class RequestPriority : u8;
+enum class RequestRedirect : u8;
+enum class ResizeObserverBoxOptions : u8;
+enum class ResponseType : u8;
+enum class TextTrackKind : u8;
+enum class TransferFunction : u8;
+enum class XMLHttpRequestResponseType : u8;
 }
 
 namespace Web::Clipboard {

Meta/Lagom/Tools/CodeGenerators/LibWeb/BindingsGenerator/IDLGenerators.cpp

@@ -14,6 +14,7 @@
 #include "Namespaces.h"
 #include <AK/Array.h>
 #include <AK/LexicalPath.h>
+#include <AK/NumericLimits.h>
 #include <AK/Queue.h>
 #include <AK/QuickSort.h>
 #include <LibIDL/Types.h>
@@ -2856,6 +2857,18 @@ JS::ThrowCompletionOr<GC::Ref<JS::Object>> @constructor_class@::construct([[mayb
     }
 }
 
+static ByteString get_best_value_for_underlying_enum_type(size_t size)
+{
+
+    if (size < NumericLimits<u8>::max()) {
+        return "u8";
+    } else if (size < NumericLimits<u16>::max()) {
+        return "u16";
+    }
+
+    VERIFY_NOT_REACHED();
+}
+
 static void generate_enumerations(HashMap<ByteString, Enumeration> const& enumerations, StringBuilder& builder)
 {
     SourceGenerator generator { builder };
@@ -2865,8 +2878,9 @@ static void generate_enumerations(HashMap<ByteString, Enumeration> const& enumer
             continue;
         auto enum_generator = generator.fork();
         enum_generator.set("enum.type.name", it.key);
+        enum_generator.set("enum.underlying_type", get_best_value_for_underlying_enum_type(it.value.translated_cpp_names.size()));
         enum_generator.append(R"~~~(
-enum class @enum.type.name@ {
+enum class @enum.type.name@ : @enum.underlying_type@ {
 )~~~");
         for (auto const& entry : it.value.translated_cpp_names) {
             enum_generator.set("enum.entry", entry.value);