Add InvalidArgument error type for NotificationDatabase.

content/browser/notifications/notification_database.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_BROWSER_NOTIFICATIONS_NOTIFICATION_DATABASE_H_
 #define CONTENT_BROWSER_NOTIFICATIONS_NOTIFICATION_DATABASE_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 43 matching lines @@
 
     // General failure code. More specific failures should be used if available.
     STATUS_ERROR_FAILED = 3,
 
     // leveldb failed due to I/O error (read-only, full disk, etc.).
     STATUS_IO_ERROR = 4,
 
     // leveldb operation not supported
     STATUS_NOT_SUPPORTED = 5,
 
+    // Invalid database ID or snapshot ID provided.
+    STATUS_INVALID_ARGUMENT = 6,

[Peter Beverloo, 2016/06/21 11:00:33]

Please update the NotificationDatabaseStatus enumeration in histograms.xml.

+
     // Number of entries in the status enumeration. Used by UMA. Must always be
     // one higher than the otherwise highest value in this enumeration.
-    STATUS_COUNT = 6
+    STATUS_COUNT = 7
   };
 
   explicit NotificationDatabase(const base::FilePath& path);
   ~NotificationDatabase();
 
   // Opens the database. If |path| is non-empty, it will be created on the given
   // directory on the filesystem. If |path| is empty, the database will be
   // created in memory instead, and its lifetime will be tied to this instance.
   // |create_if_missing| determines whether to create the database if necessary.
   Status Open(bool create_if_missing);
@@ skipping 118 matching lines @@
   State state_ = STATE_UNINITIALIZED;
 
   base::SequenceChecker sequence_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(NotificationDatabase);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_NOTIFICATIONS_NOTIFICATION_DATABASE_H_