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

ios/chrome/browser/ui/tab_switcher/tab_switcher_panel_controller.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_PANEL_CONTROLLER_H_
 #define IOS_CHROME_BROWSER_UI_TAB_SWITCHER_TAB_SWITCHER_PANEL_CONTROLLER_H_
 
 #import <UIKit/UIKit.h>
 
 #include "base/ios/block_types.h"
@@ skipping 32 matching lines @@
 @end
 
 @class TabSwitcherPanelView;
 // The tab switcher panel controller manages a panel view.
 // It can manage either distant or local sessions and uses a TabSwitcherModel
 // as its data source.
 @class TabSwitcherCache;
 
 @interface TabSwitcherPanelController : NSObject
 
-@property(nonatomic, readonly) TabSwitcherPanelView* view;
-@property(nonatomic, assign) id<TabSwitcherPanelControllerDelegate> delegate;
+@property(unsafe_unretained, nonatomic, readonly) TabSwitcherPanelView* view;
+@property(nonatomic, unsafe_unretained) id<TabSwitcherPanelControllerDelegate>
+    delegate;
 @property(nonatomic, readonly) TabSwitcherSessionType sessionType;
 
 // Initializes a controller for a view showing local tabs. |offTheRecord|
 // determines whether the tabs will be shown for the incognito browser state or
 // not. |model| is used to populate the view and must not be nil.
 - (instancetype)initWithModel:(TabSwitcherModel*)model
         forLocalSessionOfType:(TabSwitcherSessionType)type
                     withCache:(TabSwitcherCache*)cache
                  browserState:(ios::ChromeBrowserState*)browserState;
 
@@ skipping 27 matching lines @@
 - (void)reload;
 
 - (UICollectionView*)collectionView;
 
 // Returns the distantSession owned and displayed by this controller.
 - (const synced_sessions::DistantSession*)distantSession;
 
 @end
 
 #endif  // IOS_CHROME_BROWSER_UI_TAB_SWITCHER_TAB_SWITCHER_PANEL_CONTROLLER_H_