[web] Assign default natural width/height for svgs that report 0,0 on firefox and ie11 (#22184)

lib/web_ui/lib/src/engine/html_image_codec.dart

@@ -39,10 +39,20 @@ class HtmlCodec implements ui.Codec {
       js_util.setProperty(imgElement, 'decoding', 'async');
       imgElement.decode().then((dynamic _) {
         chunkCallback?.call(100, 100);
+        int naturalWidth = imgElement.naturalWidth;
+        int naturalHeight = imgElement.naturalHeight;
+        // Workaround for https://bugzilla.mozilla.org/show_bug.cgi?id=700533.
+        if (naturalWidth == 0 && naturalHeight == 0 && (
+            browserEngine == BrowserEngine.firefox ||
+                browserEngine == BrowserEngine.ie11)) {
+          const int kDefaultImageSizeFallback = 300;
+          naturalWidth = kDefaultImageSizeFallback;
+          naturalHeight = kDefaultImageSizeFallback;
+        }
         final HtmlImage image = HtmlImage(
           imgElement,
-          imgElement.naturalWidth,
-          imgElement.naturalHeight,
+          naturalWidth,
+          naturalHeight,
         );
         completer.complete(SingleFrameInfo(image));
       }).catchError((dynamic e) {

lib/web_ui/test/engine/image/html_image_codec_test.dart

@@ -80,6 +80,24 @@ void testMain() async {
       await codec.getNextFrame();
       expect(buffer.toString(), '0/100,100/100,');
     });
+
+    /// Regression test for Firefox/ie11
+    /// https://github.com/flutter/flutter/issues/66412
+    test('Returns nonzero natural width/height', () async {
+      final HtmlCodec codec = HtmlCodec(
+          'data:image/svg+xml;base64,PHN2ZyByb2xlPSJpbWciIHZpZXdCb3g9I'
+          'jAgMCAyNCAyNCIgeG1sbnM9Imh0dHA6Ly93d3cudzMub3JnLzIwMDAvc3ZnIj48dG'
+          'l0bGU+QWJzdHJhY3QgaWNvbjwvdGl0bGU+PHBhdGggZD0iTTEyIDBjOS42MDEgMCAx'
+          'MiAyLjM5OSAxMiAxMiAwIDkuNjAxLTIuMzk5IDEyLTEyIDEyLTkuNjAxIDAtMTItMi'
+          '4zOTktMTItMTJDMCAyLjM5OSAyLjM5OSAwIDEyIDB6bS0xLjk2OSAxOC41NjRjMi41'
+          'MjQuMDAzIDQuNjA0LTIuMDcgNC42MDktNC41OTUgMC0yLjUyMS0yLjA3NC00LjU5NS'
+          '00LjU5NS00LjU5NVM1LjQ1IDExLjQ0OSA1LjQ1IDEzLjk2OWMwIDIuNTE2IDIuMDY1'
+          'IDQuNTg4IDQuNTgxIDQuNTk1em04LjM0NC0uMTg5VjUuNjI1SDUuNjI1djIuMjQ3aD'
+          'EwLjQ5OHYxMC41MDNoMi4yNTJ6bS04LjM0NC02Ljc0OGEyLjM0MyAyLjM0MyAwIDEx'
+          'LS4wMDIgNC42ODYgMi4zNDMgMi4zNDMgMCAwMS4wMDItNC42ODZ6Ii8+PC9zdmc+');
+      final ui.FrameInfo frameInfo = await codec.getNextFrame();
+      expect(frameInfo.image.width, isNot(0));
+    });
   });
 
   group('ImageCodecUrl', () {