Refactor Reading List Model to use URL as key.

ios/chrome/browser/reading_list/reading_list_model_observer.h

 // Copyright 2016 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 IOS_CHROME_BROWSER_READING_LIST_READING_LIST_MODEL_OBSERVER_H_
 #define IOS_CHROME_BROWSER_READING_LIST_READING_LIST_MODEL_OBSERVER_H_
 
-#import <set>
-#import <vector>
+#import <url/gurl.h>
 
 class ReadingListModel;
 class ReadingListEntry;
 
 // Observer for the Reading List model. In the observer methods care should be
 // taken to not modify the model.
 class ReadingListModelObserver {
  public:
   // Invoked when the model has finished loading. Until this method is called it
   // is unsafe to use the model.
   virtual void ReadingListModelLoaded(const ReadingListModel* model) = 0;
 
   // Invoked when the batch updates are about to start. It will only be called
   // once before ReadingListModelCompletedBatchUpdates, even if several updates
   // are taking place at the same time.
   virtual void ReadingListModelBeganBatchUpdates(
       const ReadingListModel* model) {}
 
   // Invoked when the batch updates have completed. This is called once all
   // batch updates are completed.
   virtual void ReadingListModelCompletedBatchUpdates(
       const ReadingListModel* model) {}
 
   // Invoked from the destructor of the model. The model is no longer valid
   // after this call. There is no need to call RemoveObserver on the model from
   // here, as the observers are automatically deleted.
   virtual void ReadingListModelBeingDeleted(const ReadingListModel* model) {}
 
   // Invoked when elements are about to be removed from the read or unread list.
-  virtual void ReadingListWillRemoveUnreadEntry(const ReadingListModel* model,
-                                                size_t index) {}
-  virtual void ReadingListWillRemoveReadEntry(const ReadingListModel* model,
-                                              size_t index) {}
+  virtual void ReadingListWillRemoveEntry(const ReadingListModel* model,
+                                          const GURL& url) {}
   // Invoked when elements are moved from unread to read or from read to unread.
   // |index| is the original position  and |read| the origin status. The element
   // will change list and/or index but will not be deleted.
   virtual void ReadingListWillMoveEntry(const ReadingListModel* model,
-                                        size_t index,
-                                        bool read) {}
+                                        const GURL& url) {}
 
   // Invoked when elements are added to the read or the unread list. The new
   // entries are always added at the beginning. these methods may be called
   // multiple time (to process changes coming from a synchronization for
   // example) and they will be executed in call order, the last call will end up
   // in first position.
-  virtual void ReadingListWillAddUnreadEntry(const ReadingListModel* model,
-                                             const ReadingListEntry& entry) {}
-
-  virtual void ReadingListWillAddReadEntry(const ReadingListModel* model,
-                                           const ReadingListEntry& entry) {}
+  virtual void ReadingListWillAddEntry(const ReadingListModel* model,
+                                       const ReadingListEntry& entry) {}
 
   // Invoked when an entry is about to change.
-  virtual void ReadingListWillUpdateUnreadEntry(const ReadingListModel* model,
-                                                size_t index) {}
-  virtual void ReadingListWillUpdateReadEntry(const ReadingListModel* model,
-                                              size_t index) {}
+  virtual void ReadingListWillUpdateEntry(const ReadingListModel* model,
+                                          const GURL& url) {}
 
   // Called after all the changes signaled by calls to the "Will" methods are
   // done. All the "Will" methods are called as necessary, then the changes
   // are applied and then this method is called.
   virtual void ReadingListDidApplyChanges(ReadingListModel* model) {}
 
  protected:
   ReadingListModelObserver() {}
   virtual ~ReadingListModelObserver() {}
 
   DISALLOW_COPY_AND_ASSIGN(ReadingListModelObserver);
 };
 
 #endif  // IOS_CHROME_BROWSER_READING_LIST_READING_LIST_MODEL_OBSERVER_H_