Go back to the old method of doing file drop promises.

content/browser/web_contents/web_contents_view_mac.mm

Index: content/browser/web_contents/web_contents_view_mac.mm
diff --git a/content/browser/web_contents/web_contents_view_mac.mm b/content/browser/web_contents/web_contents_view_mac.mm
index 6a9459d3e95c487ad9d53e0186ca247c2505dc1f..d1ab628b33e0117d58a606267a604ac5f9661bda 100644
--- a/content/browser/web_contents/web_contents_view_mac.mm
+++ b/content/browser/web_contents/web_contents_view_mac.mm
@@ -512,6 +512,18 @@ void WebContentsViewMac::CloseTab() {
   [dragSource_ moveDragTo:screenPoint];
 }
 
+// Called when a file drag is dropped and the promised files need to be written.
+- (NSArray*)namesOfPromisedFilesDroppedAtDestination:(NSURL*)dropDest {
+  if (![dropDest isFileURL])
+    return nil;
+
+  NSString* fileName = [dragSource_ dragPromisedFileTo:[dropDest path]];
+  if (!fileName)
+    return nil;
+
+  return @[ fileName ];
+}
+
 // NSDraggingDestination methods
 
 - (NSDragOperation)draggingEntered:(id<NSDraggingInfo>)sender {