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 cf8c6ad8728f97683e07e0b4d3e8d8dded8f358e..27010c3987f5f642c96ddacbed0542c274b1e593 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
@@ -322,6 +322,17 @@ 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