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

ios/chrome/browser/ui/tab_switcher/tab_switcher_view.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_BROWSER_UI_TAB_SWITCHER_TAB_SWITCHER_VIEW_H_
 #define IOS_CHROME_BROWSER_UI_TAB_SWITCHER_TAB_SWITCHER_VIEW_H_
 
 #import <UIKit/UIKit.h>
 
 #import "ios/chrome/browser/ui/tab_switcher/tab_switcher_model.h"
@@ skipping 10 matching lines @@
 - (void)openNewTabInPanelAtIndex:(NSInteger)panelIndex;
 - (ios_internal::NewTabButtonStyle)buttonStyleForPanelAtIndex:
     (NSInteger)panelIndex;
 - (BOOL)shouldShowDismissButtonForPanelAtIndex:(NSInteger)panelIndex;
 - (void)tabSwitcherViewDelegateDismissTabSwitcher:(TabSwitcherView*)delegate;
 
 @end
 
 @interface TabSwitcherView : UIView<UIScrollViewDelegate>
 
-@property(nonatomic, readonly) TabSwitcherHeaderView* headerView;
-@property(nonatomic, readonly) UIScrollView* scrollView;
+@property(unsafe_unretained, nonatomic, readonly)
+    TabSwitcherHeaderView* headerView;
+@property(unsafe_unretained, nonatomic, readonly) UIScrollView* scrollView;
 
-@property(nonatomic, assign) id<TabSwitcherViewDelegate> delegate;
+@property(nonatomic, unsafe_unretained) id<TabSwitcherViewDelegate> delegate;
 
 // Select the panel at the given index, updating both the header and content.
 // The panel selection will be animated if VoiceOver is disabled.
 - (void)selectPanelAtIndex:(NSInteger)index;
 // Adds the view |view| at index |index|.
 - (void)addPanelView:(UIView*)view atIndex:(NSUInteger)index;
 // Removes the view at index |index| and update scrollview.
 - (void)removePanelViewAtIndex:(NSUInteger)index;
 // Removes the view at index |index| and update scrollview if |update| is true.
 - (void)removePanelViewAtIndex:(NSUInteger)index updateScrollView:(BOOL)update;
 // Returns the index of the currently selected panel.
 - (NSInteger)currentPanelIndex;
 // Updates the state of the tab switcher overlay buttons.
 // Overlay buttons are the top right dismiss button and the bottom right new tab
 // button.
 - (void)updateOverlayButtonState;
 
 @end
 
 #endif  // IOS_CHROME_BROWSER_UI_TAB_SWITCHER_TAB_SWITCHER_VIEW_H_