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

ios/chrome/browser/ui/ntp/new_tab_page_toolbar_controller.h

 // 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.
 
 #ifndef IOS_CHROME_BROWSER_UI_NTP_NEW_TAB_PAGE_TOOLBAR_CONTROLLER_H_
 #define IOS_CHROME_BROWSER_UI_NTP_NEW_TAB_PAGE_TOOLBAR_CONTROLLER_H_
 
 #import "ios/chrome/browser/ui/toolbar/toolbar_controller.h"
 
 @protocol GoogleLandingDataSource;
 @protocol UrlLoader;
 @protocol OmniboxFocuser;
 @protocol WebToolbarDelegate;
 
 // New tab page specific toolbar. The background view is hidden and the
 // navigation buttons are also hidden if there is no forward history. Does not
 // contain an omnibox but tapping in the center will focus the main toolbar's
 // omnibox.
 @interface NewTabPageToolbarController : ToolbarController
 
 // Designated initializer. The underlying ToolbarController is initialized with
 // ToolbarControllerStyleLightMode.
 - (instancetype)init;
 
-@property(nonatomic, assign) id<UrlLoader, OmniboxFocuser, WebToolbarDelegate>
+@property(nonatomic, weak) id<UrlLoader, OmniboxFocuser, WebToolbarDelegate>
     dispatcher;
 
 // |YES| if the toolbar can show the forward arrow.
 - (void)setCanGoForward:(BOOL)canGoForward;
 
 // |YES| if the toolbar can show the back arrow.
 - (void)setCanGoBack:(BOOL)canGoBack;
 
 @end
 
 #endif  // IOS_CHROME_BROWSER_UI_NTP_NEW_TAB_PAGE_TOOLBAR_CONTROLLER_H_