Mac: Make ScopedTypeRef require explicit constructors

components/bookmarks/browser/bookmark_pasteboard_helper_mac.mm

 // Copyright 2014 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.
 
 #include "components/bookmarks/browser/bookmark_pasteboard_helper_mac.h"
 
 #import <Cocoa/Cocoa.h>
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 210 matching lines @@
   if ([urls count] > 0) {
     if ([urls count] == 1) {
       item = ui::ClipboardUtil::PasteboardItemFromUrl([urls firstObject],
                                                       [url_titles firstObject]);
     } else {
       item = ui::ClipboardUtil::PasteboardItemFromUrls(urls, url_titles);
     }
   }
 
   if (!item) {
-    item = [[NSPasteboardItem alloc] init];
+    item.reset([[NSPasteboardItem alloc] init]);
   }
 
   [item setString:[toplevel_string_data componentsJoinedByString:@"\n"]
           forType:NSPasteboardTypeString];
   return item;
 }
 
 NSPasteboard* PasteboardFromType(ui::ClipboardType type) {
   NSString* type_string = nil;
   switch (type) {
@@ skipping 59 matching lines @@
   NSPasteboard* pb = PasteboardFromType(type);
 
   NSArray* availableTypes = @[
     ui::ClipboardUtil::UTIForWebURLsAndTitles(),
     ui::ClipboardUtil::UTIForPasteboardType(kBookmarkDictionaryListPboardType)
   ];
   return [pb availableTypeFromArray:availableTypes] != nil;
 }
 
 }  // namespace bookmarks