Revert of Add Store+Sync to reading list.

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>
 
@@ skipping 23 matching lines @@
   // 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) {}
   // 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.
+  // |index| is the original position in the origin list. The element will be
+  // added to the beginning of the target list.
   virtual void ReadingListWillMoveEntry(const ReadingListModel* model,
-                                        size_t index,
-                                        bool read) {}
+                                        size_t index) {}
 
   // 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,
@@ skipping 11 matching lines @@
   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_