Add end to end test for Media galleries scan API.

chrome/browser/ui/views/extensions/media_galleries_scan_result_dialog_views.cc

Index: chrome/browser/ui/views/extensions/media_galleries_scan_result_dialog_views.cc
diff --git a/chrome/browser/ui/views/extensions/media_galleries_scan_result_dialog_views.cc b/chrome/browser/ui/views/extensions/media_galleries_scan_result_dialog_views.cc
index 46d2af6664a841ee4cc036fd688e87c407ca510b..12f2a7f03f651854f3420f889caa12df0b99b082 100644
--- a/chrome/browser/ui/views/extensions/media_galleries_scan_result_dialog_views.cc
+++ b/chrome/browser/ui/views/extensions/media_galleries_scan_result_dialog_views.cc
@@ -325,6 +325,17 @@ void MediaGalleriesScanResultDialogViews::ShowContextMenu(
   }
 }
 
+void MediaGalleriesScanResultDialogViews::AcceptDialogForTesting() {
+  accepted_ = true;
+
+  web_modal::WebContentsModalDialogManager* web_contents_modal_dialog_manager =
+      web_modal::WebContentsModalDialogManager::FromWebContents(
+          controller_->web_contents());
+  DCHECK(web_contents_modal_dialog_manager);
+  web_modal::WebContentsModalDialogManager::TestApi(
+      web_contents_modal_dialog_manager).CloseAllDialogs();
+}
+
 // MediaGalleriesScanResultDialogViewsController -------------------------------
 
 // static