[ObjC ARC] Converts ios/chrome/browser/ui/history:history to ARC.

ios/chrome/browser/ui/history/history_entry_inserter.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_UI_HISTORY_HISTORY_ENTRY_INSERTER_H_
 #define IOS_CHROME_BROWSER_UI_HISTORY_HISTORY_ENTRY_INSERTER_H_
 
 #import <Foundation/Foundation.h>
 
 #import "ios/chrome/browser/ui/collection_view/collection_view_model.h"
@@ skipping 18 matching lines @@
 - (void)historyEntryInserter:(HistoryEntryInserter*)inserter
      didRemoveSectionAtIndex:(NSInteger)sectionIndex;
 @end
 
 // Object for ensuring history entry items are kept in order as they are added
 // to the CollectionViewModel.
 @interface HistoryEntryInserter : NSObject
 
 // Delegate for the HistoryEntryInserter. Receives callbacks upon item and
 // section insertion and removal.
-@property(nonatomic, assign) id<HistoryEntryInserterDelegate> delegate;
+@property(nonatomic, weak) id<HistoryEntryInserterDelegate> delegate;
 
 // Designated initializer for HistoryEntryInserter. collectionViewModel is the
 // model into which entries are inserted. Sections for history entries are
 // appended to the model. Sections already in the model at initialization
 // of the inserter should not be removed, and sections should not be added
 // except by the inserter. Duplicate entries are not inserted.
 - (instancetype)initWithModel:(CollectionViewModel*)collectionViewModel
     NS_DESIGNATED_INITIALIZER;
 - (instancetype)init NS_UNAVAILABLE;
 
 // Inserts a history entry into the model at the correct sorted index path.
 // History entries in the model are sorted from most to least recent, and
 // grouped into section by date. Duplicate entries are not inserted. Invokes
 // delegate callback when insertion is complete.
 - (void)insertHistoryEntryItem:(HistoryEntryItem*)item;
 
 // Returns section identifier for provided timestamp. Adds section for date if
 // not found, and invokes delegate callback.
 - (NSUInteger)sectionIdentifierForTimestamp:(base::Time)timestamp;
 
 // Removes section at |sectionIndex|, and invokes delegate callback when removal
 // is complete.
 - (void)removeSection:(NSInteger)sectionIndex;
 
 @end
 
 #endif  // IOS_CHROME_BROWSER_UI_HISTORY_HISTORY_ENTRY_INSERTER_H_