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

ios/chrome/browser/ui/popup_menu/popup_menu_view.mm

 // Copyright 2012 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.
 
 #import "ios/chrome/browser/ui/popup_menu/popup_menu_view.h"
 
 #import <QuartzCore/QuartzCore.h>
 
-#include "base/mac/scoped_nsobject.h"
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
 
 namespace {
 // The image edge insets for popup_background.png.
 NS_INLINE UIEdgeInsets PopupBackgroundInsets() {
   return UIEdgeInsetsMake(28, 28, 28, 28);
 }
 };
 
 @implementation PopupMenuView {
-  base::scoped_nsobject<UIImageView> imageView_;
+  UIImageView* imageView_;
 }
 
 @synthesize delegate = delegate_;
 
 - (instancetype)initWithFrame:(CGRect)frame {
   self = [super initWithFrame:frame];
   if (self)
     [self commonInitialization];
 
   return self;
 }
 
 - (instancetype)initWithCoder:(NSCoder*)aDecoder {
   self = [super initWithCoder:aDecoder];
   if (self)
     [self commonInitialization];
 
   return self;
 }
 
 - (void)commonInitialization {
   UIImage* image = [UIImage imageNamed:@"popup_background"];
   image = [image resizableImageWithCapInsets:PopupBackgroundInsets()];
 
-  imageView_.reset([[UIImageView alloc] initWithImage:image]);
+  imageView_ = [[UIImageView alloc] initWithImage:image];
   [self addSubview:imageView_];
 }
 
 - (void)layoutSubviews {
   [super layoutSubviews];
   [imageView_ setFrame:[self bounds]];
 }
 
 - (BOOL)accessibilityPerformEscape {
   if (delegate_) {
     [delegate_ dismissPopupMenu];
     UIAccessibilityPostNotification(UIAccessibilityScreenChangedNotification,
                                     nil);
     return YES;
   }
   return NO;
 }
 
 @end