diff --git a/browser_patches/webkit/BUILD_NUMBER b/browser_patches/webkit/BUILD_NUMBER
index b50ff03925..3b55e7c1d6 100644
--- a/browser_patches/webkit/BUILD_NUMBER
+++ b/browser_patches/webkit/BUILD_NUMBER
@@ -1,2 +1,2 @@
-1377
-Changed: yurys@chromium.org Tue 03 Nov 2020 03:59:48 PM PST
+1378
+Changed: yurys@chromium.org Tue Nov  3 18:28:54 PST 2020
diff --git a/browser_patches/webkit/embedder/Playwright/mac/AppDelegate.m b/browser_patches/webkit/embedder/Playwright/mac/AppDelegate.m
index 45d2309b76..682d78e29a 100644
--- a/browser_patches/webkit/embedder/Playwright/mac/AppDelegate.m
+++ b/browser_patches/webkit/embedder/Playwright/mac/AppDelegate.m
@@ -358,6 +358,7 @@ const NSActivityOptions ActivityOptions =
 #pragma mark WKUIDelegate
 
 - (void)webViewDidClose:(WKWebView *)webView {
+    [self webView:webView handleJavaScriptDialog:false value:nil];
     for (NSWindow *window in _headlessWindows) {
         if (webView.window != window)
             continue;
diff --git a/browser_patches/webkit/embedder/Playwright/mac/BrowserWindowController.m b/browser_patches/webkit/embedder/Playwright/mac/BrowserWindowController.m
index ca160302b8..4856e09e28 100644
--- a/browser_patches/webkit/embedder/Playwright/mac/BrowserWindowController.m
+++ b/browser_patches/webkit/embedder/Playwright/mac/BrowserWindowController.m
@@ -418,6 +418,7 @@ static BOOL areEssentiallyEqual(double a, double b)
 }
 
 - (void)webViewDidClose:(WKWebView *)webView {
+    [self webView:webView handleJavaScriptDialog:false value:nil];
     [self.window close];
 }