browser(webkit): make blob downloads work on Mac (#1971)

Author: yury-s

browser_patches/webkit/BUILD_NUMBER

@@ -1 +1 @@
-1210
+1211

browser_patches/webkit/src/Tools/Playwright/mac/AppDelegate.m

@@ -372,6 +372,10 @@ - (void)webView:(WKWebView *)webView decidePolicyForNavigationAction:(WKNavigati
 {
     LOG(@"decidePolicyForNavigationAction");
 
+    if (navigationAction._shouldPerformDownload) {
+        decisionHandler(_WKNavigationActionPolicyDownload);
+        return;
+    }
     if (navigationAction._canHandleRequest) {
         decisionHandler(WKNavigationActionPolicyAllow);
         return;