Add notifications to allow desktop notification permissions to be synced.

base/values.h

 // Copyright (c) 2010 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.
 
 // This file specifies a recursive data storage class called Value
 // intended for storing setting and other persistable data.
 // It includes the ability to specify (recursive) lists and dictionaries, so
 // it's fairly expressive.  However, the API is optimized for the common case,
 // namely storing a hierarchical tree of simple values.  Given a
 // DictionaryValue root, you can easily do things like:
@@ skipping 383 matching lines @@
   // it will return false and the ListValue object will be unchanged.
   bool Remove(size_t index, Value** out_value);
 
   // Removes the first instance of |value| found in the list, if any, and
   // deletes it.  Returns the index that it was located at (-1 for not present).
   int Remove(const Value& value);
 
   // Appends a Value to the end of the list.
   void Append(Value* in_value);
 
+  // Appends a Value if it's not already present.
+  // Returns true if successful, or false if the value was already present.
+  bool AppendIfNotPresent(Value* in_value);
+
   // Insert a Value at index.
   // Returns true if successful, or false if the index was out of range.
   bool Insert(size_t index, Value* in_value);
 
   // Iteration
   typedef ValueVector::iterator iterator;
   typedef ValueVector::const_iterator const_iterator;
 
   ListValue::iterator begin() { return list_.begin(); }
   ListValue::iterator end() { return list_.end(); }
@@ skipping 18 matching lines @@
   // This method deserializes the subclass-specific format into a Value object.
   // If the return value is non-NULL, the caller takes ownership of returned
   // Value. If the return value is NULL, and if error_code is non-NULL,
   // error_code will be set with the underlying error.
   // If |error_message| is non-null, it will be filled in with a formatted
   // error message including the location of the error if appropriate.
   virtual Value* Deserialize(int* error_code, std::string* error_str) = 0;
 };
 
 #endif  // BASE_VALUES_H_