[ObjC ARC] Converts ios/chrome/app/spotlight:spotlight to ARC.

ios/chrome/app/spotlight/bookmarks_spotlight_manager.h

 // Copyright 2015 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_APP_SPOTLIGHT_BOOKMARKS_SPOTLIGHT_MANAGER_H_
 #define IOS_CHROME_APP_SPOTLIGHT_BOOKMARKS_SPOTLIGHT_MANAGER_H_
 
 #import "ios/chrome/app/spotlight/base_spotlight_manager.h"
 
 namespace bookmarks {
@@ skipping 11 matching lines @@
 @protocol BookmarkUpdatedDelegate
 
 // Called when a bookmark is updated.
 - (void)bookmarkUpdated;
 
 @end
 
 @interface BookmarksSpotlightManager : BaseSpotlightManager
 
 // The delegate notified when a bookmark is updated.
-@property(nonatomic, assign) id<BookmarkUpdatedDelegate> delegate;
+@property(nonatomic, weak) id<BookmarkUpdatedDelegate> delegate;
 
 + (BookmarksSpotlightManager*)bookmarksSpotlightManagerWithBrowserState:
     (ios::ChromeBrowserState*)browserState;
 
 // Checks the date of the latest global indexation and reindex all bookmarks if
 // needed.
 - (void)reindexBookmarksIfNeeded;
 
 // Methods below here are for testing use only.
 
 - (instancetype)
 initWithLargeIconService:(favicon::LargeIconService*)largeIconService
            bookmarkModel:(bookmarks::BookmarkModel*)bookmarkModel;
 
 // Recursively adds node ancestors titles to keywords. Permanent nodes are
 // ignored.
 - (void)getParentKeywordsForNode:(const bookmarks::BookmarkNode*)node
                          inArray:(NSMutableArray*)keywords;
 
 // Adds keywords to |item|.
 - (void)addKeywords:(NSArray*)keywords toSearchableItem:(CSSearchableItem*)item;
 
 @end
 
 #endif  // IOS_CHROME_APP_SPOTLIGHT_BOOKMARKS_SPOTLIGHT_MANAGER_H_