Add GetEntryFromURL method to the ReadingListModel.

ios/chrome/browser/reading_list/reading_list_model.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_H_
 #define IOS_CHROME_BROWSER_READING_LIST_READING_LIST_MODEL_H_
 
 #include <memory>
 #include <string>
 #include <vector>
@@ skipping 35 matching lines @@
   // Returns the size of read and unread entries.
   virtual size_t unread_size() const = 0;
   virtual size_t read_size() const = 0;
 
   // Returns true if there are entries in the model that were not seen by the
   // user yet. Reset to true when new unread entries are added. Reset to false
   // when ResetUnseenEntries is called.
   virtual bool HasUnseenEntries() const = 0;
   virtual void ResetUnseenEntries() = 0;
 
+  // TODO(659099): Remove methods.
   // Returns a specific entry.
   virtual const ReadingListEntry& GetUnreadEntryAtIndex(size_t index) const = 0;
   virtual const ReadingListEntry& GetReadEntryAtIndex(size_t index) const = 0;
 
+  // Returns a specific entry. Returns null if the entry does not exist.
+  virtual const ReadingListEntry* GetEntryFromURL(const GURL& gurl) const = 0;
+
   // Synchronously calls the |callback| with entry associated with this |url|.
   // Does nothing if there is no entry associated.
   // Returns whether the callback has been called.
   virtual bool CallbackEntryURL(
       const GURL& url,
       base::Callback<void(const ReadingListEntry&)> callback) const = 0;
 
   // Adds |url| at the top of the unread entries, and removes entries with the
   // same |url| from everywhere else if they exist. The addition may be
   // asynchronous, and the data will be available only once the observers are
@@ skipping 53 matching lines @@
   // ReadingListBatchUpdateToken dtor.
   virtual void EndBatchUpdates();
 
  private:
   unsigned int current_batch_updates_count_;
 
   DISALLOW_COPY_AND_ASSIGN(ReadingListModel);
 };
 
 #endif  // IOS_CHROME_BROWSER_READING_LIST_READING_LIST_MODEL_H_