Firefox overlay is seen opened even if Import Overlay is Cancelled.

chrome/browser/ui/cocoa/importer/import_lock_dialog_cocoa.mm

Index: chrome/browser/ui/cocoa/importer/import_lock_dialog_cocoa.mm
diff --git a/chrome/browser/ui/cocoa/importer/import_lock_dialog_cocoa.mm b/chrome/browser/ui/cocoa/importer/import_lock_dialog_cocoa.mm
index 45b25e91b480f787e2a2314f291a6f80d67773d2..e7eb76c566bb25a88b2e8fc85e4781a6ae7bb9b0 100644
--- a/chrome/browser/ui/cocoa/importer/import_lock_dialog_cocoa.mm
+++ b/chrome/browser/ui/cocoa/importer/import_lock_dialog_cocoa.mm
@@ -36,4 +36,9 @@ void ShowImportLockDialog(gfx::NativeWindow parent,
   content::RecordAction(UserMetricsAction("ImportLockDialogCocoa_Shown"));
 }
 
+void HideImportLockDialog() {
+  // This code path is not needed for MAC ,plz refer Issue:2769383002 for
+  // Details.

[Ilya Sherman, 2017/03/30 22:14:32]

nit: I'd rephrase this a bit to something like "This code path is not needed for
Mac, as the user must explicitly close the sheet before any situation can arise
in which we'd need to close it programmatically.  See https://crbug.com/672428
for more details.  (Of note, "Mac" is used for the OS, "MAC" is used for "MAC
addresses".)

[nikhil.sahni, 2017/03/31 15:21:25]

Done.

+}
+
 }  // namespace importer