Retrive displayed notifications asynchronously

chrome/browser/notifications/notification_platform_bridge_android.cc

Index: chrome/browser/notifications/notification_platform_bridge_android.cc
diff --git a/chrome/browser/notifications/notification_platform_bridge_android.cc b/chrome/browser/notifications/notification_platform_bridge_android.cc
index 0c8c82fe6f819c043ad8bc8419020a02332cd819..c46daefb6d511d6e672fc1cdea10e012c67bb5b9 100644
--- a/chrome/browser/notifications/notification_platform_bridge_android.cc
+++ b/chrome/browser/notifications/notification_platform_bridge_android.cc
@@ -319,6 +319,18 @@ bool NotificationPlatformBridgeAndroid::GetDisplayed(
   return false;
 }
 
+void NotificationPlatformBridgeMac::GetDisplayedAsync(
+    const std::string& profile_id,
+    bool incognito,
+    const NotificationCommon::NotificationResultCallback& callback) const {
+  std::unique_ptr<std::set<std::string>> displayedNotifications =
+      base::MakeUnique<std::set<std::string>>();
+  content::BrowserThread::PostTask(
+      content::BrowserThread::IO, FROM_HERE,
+      base::Bind(callback, base::Passed(&displayedNotifications),
+                 false /* supports getting displayed notifications */));
+}
+
 // static
 bool NotificationPlatformBridgeAndroid::RegisterNotificationPlatformBridge(
     JNIEnv* env) {