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/metrics/user_metrics.h"
 #include "base/single_thread_task_runner.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);
   base::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();
+    g_widget = nullptr;
+  }
+}
+
 // 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);
   AddChildView(description_label_);
 }
 
 ImportLockDialogView::~ImportLockDialogView() {
+  g_widget = nullptr;

[nikhil.sahni, 2017/04/03 13:05:11]

Even Destructor is called on Exiting so added check here as well.

 }
 
 gfx::Size ImportLockDialogView::GetPreferredSize() const {
   return gfx::Size(views::Widget::GetLocalizedContentsSize(
       IDS_IMPORTLOCK_DIALOG_WIDTH_CHARS,
       IDS_IMPORTLOCK_DIALOG_HEIGHT_LINES));
 }
 
 void ImportLockDialogView::Layout() {
   gfx::Rect bounds(GetLocalBounds());
   bounds.Inset(views::kButtonHEdgeMarginNew,
                LayoutDelegate::Get()->GetMetric(
                    LayoutDelegate::Metric::PANEL_CONTENT_MARGIN));
   description_label_->SetBoundsRect(bounds);
 }
 
 base::string16 ImportLockDialogView::GetDialogButtonLabel(
     ui::DialogButton button) const {
   return l10n_util::GetStringUTF16((button == ui::DIALOG_BUTTON_OK) ?
       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;

[nikhil.sahni, 2017/04/03 13:05:11]

On Pressing "Continue" this function gets called so setting 
to nullptr here as well.

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

[nikhil.sahni, 2017/04/03 13:05:11]

On pressing "Skip Import" and "Cross Button of the Lock Dialog" this function
gets called as it is mapped with CANCEL so for safety making it nullptr here as
well. 

   return true;
 }