mash: Replace int ShelfIDs with AppLaunchID strings.

chrome/browser/ui/ash/launcher/settings_window_observer.cc

Index: chrome/browser/ui/ash/launcher/settings_window_observer.cc
diff --git a/chrome/browser/ui/ash/launcher/settings_window_observer.cc b/chrome/browser/ui/ash/launcher/settings_window_observer.cc
index c7fa01abeea8768ab2cb4fb4a457deb9062a13b7..83ed6871f0dd6c243e9ef4655a1992a1b1df999e 100644
--- a/chrome/browser/ui/ash/launcher/settings_window_observer.cc
+++ b/chrome/browser/ui/ash/launcher/settings_window_observer.cc
@@ -52,6 +52,9 @@ SettingsWindowObserver::~SettingsWindowObserver() {
 void SettingsWindowObserver::OnNewSettingsWindow(Browser* settings_browser) {
   aura::Window* window = settings_browser->window()->GetNativeWindow();
   window->SetTitle(l10n_util::GetStringUTF16(IDS_SETTINGS_TITLE));
+  // An app id for settings windows, also used to identify the shelf item.
+  static constexpr char kSettingsId[] = "SettingsId";
+  window->SetProperty(ash::kShelfIDKey, new ash::ShelfID(kSettingsId));
   window->SetProperty<int>(ash::kShelfItemTypeKey, ash::TYPE_DIALOG);
   ui::ResourceBundle& rb = ui::ResourceBundle::GetSharedInstance();
   // The new gfx::ImageSkia instance is owned by the window itself.