arc: Handle default app not availble case.

chrome/browser/ui/app_list/arc/arc_default_app_list.cc

Index: chrome/browser/ui/app_list/arc/arc_default_app_list.cc
diff --git a/chrome/browser/ui/app_list/arc/arc_default_app_list.cc b/chrome/browser/ui/app_list/arc/arc_default_app_list.cc
index 1e02251f5438afe5219508ae63607f117f176dd5..602fcc5d43586df9d655acf0c2b14cbf0662adf7 100644
--- a/chrome/browser/ui/app_list/arc/arc_default_app_list.cc
+++ b/chrome/browser/ui/app_list/arc/arc_default_app_list.cc
@@ -201,6 +201,15 @@ void ArcDefaultAppList::MaybeMarkPackageUninstalled(
   it->second = uninstalled;
 }
 
+std::unordered_set<std::string> ArcDefaultAppList::GetActivePackages() const {
+  std::unordered_set<std::string> result;
+  for (const auto& package_info : packages_) {
+    if (!package_info.second)
+      result.insert(package_info.first);
+  }
+  return result;
+}
+
 ArcDefaultAppList::AppInfo::AppInfo(const std::string& name,
                                     const std::string& package_name,
                                     const std::string& activity,