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

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

Index: chrome/browser/ui/views/importer/import_lock_dialog_view.cc
diff --git a/chrome/browser/ui/views/importer/import_lock_dialog_view.cc b/chrome/browser/ui/views/importer/import_lock_dialog_view.cc
index 71392b5908635fdeeced6d4f8fab2bd1cf316843..0876c0172cf252a0b310a29950e073ed13b5c8ce 100644
--- a/chrome/browser/ui/views/importer/import_lock_dialog_view.cc
+++ b/chrome/browser/ui/views/importer/import_lock_dialog_view.cc
@@ -30,13 +30,32 @@ void ShowImportLockDialog(gfx::NativeWindow parent,
   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(
@@ -51,6 +70,7 @@ ImportLockDialogView::ImportLockDialogView(
 }
 
 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 {
@@ -80,11 +100,13 @@ base::string16 ImportLockDialogView::GetWindowTitle() const {
 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;
 }