Consolidate two IsArcWindow functions to reduce code duplication

components/arc/arc_util.cc

Index: components/arc/arc_util.cc
diff --git a/components/arc/arc_util.cc b/components/arc/arc_util.cc
index 7c3ee3f5a080b7e1b4d0b82dc0bbc686873c5b5e..2e106f71c7853ced3ef2f7d0c00f97e124ba7199 100644
--- a/components/arc/arc_util.cc
+++ b/components/arc/arc_util.cc
@@ -6,6 +6,8 @@
 
 #include <string>
 
+#include "ash/shared/app_types.h"
+#include "ash/wm_window.h"
 #include "base/command_line.h"
 #include "base/feature_list.h"
 #include "chromeos/chromeos_switches.h"
@@ -111,4 +113,12 @@ bool IsArcOptInVerificationDisabled() {
       chromeos::switches::kDisableArcOptInVerification);
 }
 
+bool IsArcAppWindow(aura::Window* window) {
+  // The getter returns nullptr when |window| is nullptr.
+  ash::WmWindow* wm_window = ash::WmWindow::Get(window);
+  if (!wm_window)
+    return false;
+  return wm_window->GetAppType() == static_cast<int>(ash::AppType::ARC_APP);
+}
+
 }  // namespace arc