[iOS Reading List] Skip invalid images in distillation.

ios/chrome/browser/reading_list/url_downloader.cc

Index: ios/chrome/browser/reading_list/url_downloader.cc
diff --git a/ios/chrome/browser/reading_list/url_downloader.cc b/ios/chrome/browser/reading_list/url_downloader.cc
index eea31e57c0f468b03934a84e8ed29b931664be3f..b73616bcc1e8a1187e46e655922139f960e9d0cd 100644
--- a/ios/chrome/browser/reading_list/url_downloader.cc
+++ b/ios/chrome/browser/reading_list/url_downloader.cc
@@ -333,8 +333,9 @@ std::string URLDownloader::SaveAndReplaceImagesInHTML(
     // Mixed content is HTTP images on HTTPS pages.
     bool image_is_mixed_content = distilled_url_.SchemeIsCryptographic() &&
                                   !images[i].url.SchemeIsCryptographic();
-    // Only save images if it is not mixed content.
-    if (!image_is_mixed_content) {
+    // Only save images if it is not mixed content and image data is valid.
+    if (!image_is_mixed_content && images[i].url.is_valid() &&
+        !images[i].data.empty()) {
       if (!SaveImage(url, images[i].url, images[i].data, &local_image_name)) {
         return std::string();
       }