Refactor Reading List Model to use URL as key.

ios/chrome/browser/reading_list/reading_list_model_observer.h

Index: ios/chrome/browser/reading_list/reading_list_model_observer.h
diff --git a/ios/chrome/browser/reading_list/reading_list_model_observer.h b/ios/chrome/browser/reading_list/reading_list_model_observer.h
index f08d35dfdb74e489e45238d56cbc8e13da3a8072..2ee2ab5b11aac5f2c34293d5412cda6d6607e5f3 100644
--- a/ios/chrome/browser/reading_list/reading_list_model_observer.h
+++ b/ios/chrome/browser/reading_list/reading_list_model_observer.h
@@ -5,8 +5,7 @@
 #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;
@@ -36,33 +35,25 @@ class ReadingListModelObserver {
   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