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

chrome/browser/ui/views/importer/import_lock_dialog_view.cc

 // Copyright (c) 2012 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/views/importer/import_lock_dialog_view.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 12 matching lines @@
 using base::UserMetricsAction;
 
 namespace importer {
 
 void ShowImportLockDialog(gfx::NativeWindow parent,
                           const base::Callback<void(bool)>& callback) {
   ImportLockDialogView::Show(parent, callback);
   content::RecordAction(UserMetricsAction("ImportLockDialogView_Shown"));
 }
 
+void HideImportLockDialog() {
+  ImportLockDialogView::Hide();
+}
+
 }  // namespace importer
 
+// For storing widget ptr on creation of dialog widget
+// using method CreateDialogWidget.
+namespace {
+static views::Widget* g_widget = nullptr;
+}
+
+// static
+void ImportLockDialogView::Hide() {
+  if (g_widget)
+    g_widget->Close();

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

Should you set g_widget to nullptr here?

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

Done.

+}
+
 // static
 void ImportLockDialogView::Show(gfx::NativeWindow parent,
                                 const base::Callback<void(bool)>& callback) {
-  views::DialogDelegate::CreateDialogWidget(
-      new ImportLockDialogView(callback), NULL, NULL)->Show();
+  g_widget = views::DialogDelegate::CreateDialogWidget(
+      new ImportLockDialogView(callback), NULL, NULL);
+  g_widget->Show();
 }
 
 ImportLockDialogView::ImportLockDialogView(
     const base::Callback<void(bool)>& callback)
     : description_label_(NULL),
       callback_(callback) {
   description_label_ = new views::Label(
       l10n_util::GetStringUTF16(IDS_IMPORTER_LOCK_TEXT));
   description_label_->SetMultiLine(true);
   description_label_->SetHorizontalAlignment(gfx::ALIGN_LEFT);
@@ skipping 23 matching lines @@
       IDS_IMPORTER_LOCK_OK : IDS_IMPORTER_LOCK_CANCEL);
 }
 
 base::string16 ImportLockDialogView::GetWindowTitle() const {
   return l10n_util::GetStringUTF16(IDS_IMPORTER_LOCK_TITLE);
 }
 
 bool ImportLockDialogView::Accept() {
   base::ThreadTaskRunnerHandle::Get()->PostTask(FROM_HERE,
                                                 base::Bind(callback_, true));
+  g_widget = nullptr;

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

What about if the user cancels the dialog instead?  I think it's safer to listen
for the notification, in case there's any other way for the dialog to be closed,
than trying to catch every possible individual code path.

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

In case of CANCEL even the IMPORT Dialog gets closed as import is Cancelled so
in this case
there is no possibility for the user to explicitly cancel that.

I also studied views::WidgetObserver class,
I can implement soemthing like below

void ImportLockDialogView::OnWidgetDestroying(views::Widget* widget) {
  g_widget = nullptr;
}
 
but have to do  AddObserver here , I am stuck as where to do that here .

Can you please guide me on this, thanks 

[Ilya Sherman, 2017/04/04 05:39:52]

Yes, I think implementing ImportLockDialogView::OnWidgetDestroying() is the best
approach.  Please implement it as

void ImportLockDialogView::OnWidgetDestroying(views::Widget* widget) {
  g_widget = nullptr;
  widget->RemoveObserver(this);
}

You can call g_widget->AddObserver() as part of the ImportLockDialogView::Show()
function.  To do so, you'll need to capture the "new
ImportLockDialogView(callback)" in a local variable.

If you implement this approach, you then don't need any of the "g_widget =
nullptr" lines below, which is a lot less fragile to edge cases and code
refactoring.

[nikhil.sahni, 2017/04/04 09:21:40]

Done.

   return true;
 }
 
 bool ImportLockDialogView::Cancel() {
   base::ThreadTaskRunnerHandle::Get()->PostTask(FROM_HERE,
                                                 base::Bind(callback_, false));
   return true;
 }