Download Noto Color Emoji via the split woff2 fonts

DEPS

@@ -126,6 +126,7 @@ vars = {
   "upstream_boolean_selector": "https://github.com/dart-lang/boolean_selector.git",
   "upstream_boringssl_gen": "https://github.com/dart-lang/boringssl_gen.git",
   "upstream_boringssl": "https://github.com/openssl/openssl.git",
+  "upstream_brotli": "https://github.com/google/brotli.git",
   "upstream_browser_launcher": "https://github.com/dart-lang/browser_launcher.git",
   "upstream_buildroot": "https://github.com/flutter/buildroot.git",
   "upstream_cli_util": "https://github.com/dart-lang/cli_util.git",
@@ -294,6 +295,9 @@ deps = {
   'src/third_party/boringssl':
    Var('github_git') + '/dart-lang/boringssl_gen.git' + '@' + Var('dart_boringssl_gen_rev'),
 
+  'src/third_party/brotli':
+   Var('skia_git') + '/external/github.com/google/brotli.git' + '@' + 'ed1995b6bda19244070ab5d331111f16f67c8054',
+
   'src/third_party/yapf':
   Var('github_git') + '/google/yapf' + '@' + '212c5b5ad8e172d2d914ae454c121c89cccbcb35',
 

lib/web_ui/dev/generate_fallback_font_data.dart

@@ -6,6 +6,9 @@ import 'dart:convert' show jsonDecode;
 import 'dart:io' as io;
 
 import 'package:args/command_runner.dart';
+import 'package:csslib/parser.dart' as csslib;
+import 'package:csslib/visitor.dart'
+    show Declaration, FontFaceDirective, StyleSheet, UriTerm, Visitor;
 import 'package:http/http.dart' as http;
 import 'package:path/path.dart' as path;
 
@@ -56,19 +59,23 @@ class GenerateFallbackFontDataCommand extends Command<bool>
     if (response.statusCode != 200) {
       throw ToolExit('Failed to download Google Fonts list.');
     }
+    final List<String> fallbackFonts = <String>[];
     final Map<String, dynamic> googleFontsResult =
         jsonDecode(response.body) as Map<String, dynamic>;
     final List<Map<String, dynamic>> fontDatas =
         (googleFontsResult['items'] as List<dynamic>)
             .cast<Map<String, dynamic>>();
     final Map<String, Uri> urlForFamily = <String, Uri>{};
     for (final Map<String, dynamic> fontData in fontDatas) {
-      if (fallbackFonts.contains(fontData['family'])) {
+      if (apiFallbackFonts.contains(fontData['family'])) {
+        final String family = fontData['family'] as String;
         final Uri uri = Uri.parse(fontData['files']['regular'] as String)
             .replace(scheme: 'https');
-        urlForFamily[fontData['family'] as String] = uri;
+        urlForFamily[family] = uri;
+        fallbackFonts.add(family);
       }
     }
+    await addSplitFonts(fallbackFonts, urlForFamily);
     final Map<String, String> charsetForFamily = <String, String>{};
     final io.Directory fontDir = downloadTestFonts
         ? await io.Directory(path.join(
@@ -120,12 +127,6 @@ class GenerateFallbackFontDataCommand extends Command<bool>
     sb.writeln('final List<NotoFont> fallbackFonts = <NotoFont>[');
 
     for (final String family in fallbackFonts) {
-      if (family == 'Noto Emoji') {
-        sb.write(' if (!configuration.useColorEmoji)');
-      }
-      if (family == 'Noto Color Emoji') {
-        sb.write(' if (configuration.useColorEmoji)');
-      }
       sb.writeln(" NotoFont('$family', '${urlForFamily[family]!}',");
       final List<String> starts = <String>[];
       final List<String> ends = <String>[];
@@ -168,12 +169,50 @@ class GenerateFallbackFontDataCommand extends Command<bool>
     ));
     await fontDataFile.writeAsString(sb.toString());
   }
+
+  Future<void> addSplitFonts(
+      List<String> fallbackFonts, Map<String, Uri> urlForFamily) async {
+    for (final String font in splitFonts) {
+      final String modifiedFontName = font.replaceAll(' ', '+');
+      final Uri cssUri = Uri.parse(
+          'https://fonts.googleapis.com/css2?family=$modifiedFontName');
+      final http.Client client = http.Client();
+      final http.Response response =
+          await client.get(cssUri, headers: <String, String>{
+        // Spoof the User-Agent so Google Fonts serves WOFF2 fonts
+        'User-Agent':
+            'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) '
+                'Chrome/112.0.0.0 Safari/537.36'
+      });
+      final String cssString = response.body;
+      final StyleSheet stylesheet = csslib.parse(cssString);
+      final UriCollector uriCollector = UriCollector();
+      stylesheet.visit(uriCollector);
+      int familyCount = 0;
+      for (final Uri uri in uriCollector.uris) {
+        final String fontName = '$font $familyCount';
+        fallbackFonts.add(fontName);
+        urlForFamily[fontName] = uri;
+        familyCount += 1;
+      }
+    }
+    print(urlForFamily);
+  }
 }
 
-const List<String> fallbackFonts = <String>[
+class UriCollector extends Visitor {
+  final List<Uri> uris = <Uri>[];
+
+  @override
+  void visitUriTerm(UriTerm uriTerm) {
+    print(uriTerm.value);
+    uris.add(Uri.parse(uriTerm.value as String));
+  }
+}
+
+/// Fonts that should be downloaded directly from the Google Fonts API.
+const List<String> apiFallbackFonts = <String>[
   'Noto Sans',
-  'Noto Color Emoji',
-  'Noto Emoji',
   'Noto Sans Symbols',
   'Noto Sans Symbols 2',
   'Noto Sans Adlam',
@@ -315,6 +354,12 @@ const List<String> fallbackFonts = <String>[
   'Noto Sans Zanabazar Square',
 ];
 
+/// Fonts which are split up into several smaller subfonts. These need special
+/// handling.
+const List<String> splitFonts = <String>[
+  'Noto Color Emoji',
+];
+
 String _packFontRanges(List<String> starts, List<String> ends) {
   assert(starts.length == ends.length);