Make //content responsible for generating notification Ids

content/public/browser/platform_notification_context.h

Index: content/public/browser/platform_notification_context.h
diff --git a/content/public/browser/platform_notification_context.h b/content/public/browser/platform_notification_context.h
index 47d6b755a5031cd4fcda09522f0a57b69cc1d9be..07dbb6a66c9513cbc2065829b09693414c6c031d 100644
--- a/content/public/browser/platform_notification_context.h
+++ b/content/public/browser/platform_notification_context.h
@@ -34,14 +34,21 @@ class PlatformNotificationContext
 
   using WriteResultCallback =
       base::Callback<void(bool /* success */,
-                          int64_t /* notification_id */)>;
+                          const std::string& /* notification_id */)>;
 
   using DeleteResultCallback = base::Callback<void(bool /* success */)>;
 
+  // Generates a notification Id for a given |persistent_notification_id| that
+  // belongs to |origin|, and replaces notifications having the same |tag|.
+  virtual std::string GenerateNotificationId(
+      const GURL& origin,
+      const std::string& tag,
+      int64_t persistent_notification_id) = 0;
+
   // Reads the data associated with |notification_id| belonging to |origin|
   // from the database. |callback| will be invoked with the success status
   // and a reference to the notification database data when completed.
-  virtual void ReadNotificationData(int64_t notification_id,
+  virtual void ReadNotificationData(const std::string& notification_id,
                                     const GURL& origin,
                                     const ReadResultCallback& callback) = 0;
 
@@ -64,7 +71,7 @@ class PlatformNotificationContext
   // Deletes all data associated with |notification_id| belonging to |origin|
   // from the database. |callback| will be invoked with the success status
   // when the operation has completed.
-  virtual void DeleteNotificationData(int64_t notification_id,
+  virtual void DeleteNotificationData(const std::string& notification_id,
                                       const GURL& origin,
                                       const DeleteResultCallback& callback) = 0;