Ignore suggested download filename for cross origin links.

Source/core/html/HTMLAnchorElement.cpp

Index: Source/core/html/HTMLAnchorElement.cpp
diff --git a/Source/core/html/HTMLAnchorElement.cpp b/Source/core/html/HTMLAnchorElement.cpp
index 08806bc29a44ce5191a315b972796de6b1b9c831..24d9b4d13255a764636ac62e4d34cd69ee73b833 100644
--- a/Source/core/html/HTMLAnchorElement.cpp
+++ b/Source/core/html/HTMLAnchorElement.cpp
@@ -394,7 +394,10 @@ void HTMLAnchorElement::handleClick(Event* event)
                 request.setHTTPReferrer(Referrer(referrer, document().referrerPolicy()));
         }
 
-        frame->loader().client()->loadURLExternally(request, NavigationPolicyDownload, fastGetAttribute(downloadAttr));
+        bool isSameOrigin = document().securityOrigin()->canRequest(completedURL);
+        const AtomicString& suggestedName = (isSameOrigin ? fastGetAttribute(downloadAttr) : nullAtom);
+
+        frame->loader().client()->loadURLExternally(request, NavigationPolicyDownload, suggestedName);
     } else {
         FrameLoadRequest frameRequest(&document(), request, target());
         frameRequest.setTriggeringEvent(event);