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

ios/chrome/browser/passwords/password_generation_edit_view.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.
 
 #import "ios/chrome/browser/passwords/password_generation_edit_view.h"
 
 #include "base/i18n/rtl.h"
 #include "base/logging.h"
-#include "base/mac/scoped_nsobject.h"
 #include "ios/chrome/browser/passwords/password_generation_utils.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace {
 // Constants for the edit view.
 const CGFloat kEditViewFontSize = 15;
 }  // namespace
 
 @implementation PasswordGenerationEditView {
-  base::scoped_nsobject<UITextField> _textField;
+  UITextField* _textField;
 }
 
 - (instancetype)initWithPassword:(NSString*)password {
   // Frame size will updated later.
   const CGRect defaultFrameSize = CGRectMake(0, 0, 100, 30);
   self = [super initWithFrame:defaultFrameSize];
   if (self) {
-    _textField.reset([[UITextField alloc] init]);
+    _textField = [[UITextField alloc] init];
     [_textField setText:password];
     [_textField setFont:[UIFont systemFontOfSize:kEditViewFontSize]];
     [_textField setBackgroundColor:[UIColor clearColor]];
     [_textField sizeToFit];
     [_textField setUserInteractionEnabled:NO];
     [_textField setFrame:passwords::GetGenerationAccessoryFrame(
                              [self bounds], [_textField frame])];
     [_textField setAutoresizingMask:UIViewAutoresizingFlexibleTopMargin |
                                     UIViewAutoresizingFlexibleBottomMargin |
                                     UIViewAutoresizingFlexibleWidth];
     [self addSubview:_textField];
   }
   return self;
 }
 
 - (instancetype)initWithFrame:(CGRect)frame {
   NOTREACHED();
   return nil;
 }
 
 - (instancetype)initWithCoder:(NSCoder*)aDecoder {
   NOTREACHED();
   return nil;
 }
 
 @end