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

chrome/browser/ui/webui/settings/settings_import_data_handler.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/webui/settings/settings_import_data_handler.h"
 
 #include <stddef.h>
 
 #include <string>
 #include <utility>
@@ skipping 52 matching lines @@
   web_ui()->RegisterMessageCallback(
       "initializeImportDialog",
       base::Bind(&ImportDataHandler::InitializeDialog, base::Unretained(this)));
   web_ui()->RegisterMessageCallback(
       "importData",
       base::Bind(&ImportDataHandler::ImportData, base::Unretained(this)));
   web_ui()->RegisterMessageCallback(
       "importFromBookmarksFile",
       base::Bind(&ImportDataHandler::HandleChooseBookmarksFile,
                  base::Unretained(this)));
+  web_ui()->RegisterMessageCallback(
+      "closeDialog",

[Ilya Sherman, 2017/03/27 15:21:52]

Again, you'll want a more specific name, that explicitly mentions importing.

[nikhil.sahni, 2017/03/28 11:22:00]

Done.

[nikhil.sahni, 2017/03/28 11:22:00]

Done.

+      base::Bind(&ImportDataHandler::Close, base::Unretained(this)));
 }
 
 void ImportDataHandler::OnJavascriptDisallowed() {
   // Cancels outstanding profile list detections.
   importer_list_.reset();
 
   // Stops listening to updates from any ongoing imports.
   if (importer_host_)
     importer_host_->set_observer(NULL);
 }
@@ skipping 52 matching lines @@
 
   uint16_t imported_items = (selected_items & supported_items);
   if (imported_items) {
     StartImport(source_profile, imported_items);
   } else {
     LOG(WARNING) << "There were no settings to import from '"
         << source_profile.importer_name << "'.";
   }
 }
 
+void ImportDataHandler::Close(const base::ListValue* args) {
+  if (importer_host_)
+    importer_host_->NotifyImportEnded();
+}
 void ImportDataHandler::InitializeDialog(const base::ListValue* args) {
   AllowJavascript();
 
   CHECK_EQ(1U, args->GetSize());
   std::string callback_id;
   CHECK(args->GetString(0, &callback_id));
 
   importer_list_.reset(new ImporterList());
   importer_list_->DetectSourceProfiles(
       g_browser_process->GetApplicationLocale(),
@@ skipping 92 matching lines @@
                                   base::string16(),
                                   base::FilePath(),
                                   &file_type_info,
                                   0,
                                   base::FilePath::StringType(),
                                   browser->window()->GetNativeWindow(),
                                   NULL);
 }
 
 }  // namespace settings