[iOS Clean] Added dialogs UI support.

ios/clean/chrome/browser/ui/dialogs/dialog_text_field_configuration.mm

+// Copyright 2017 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/clean/chrome/browser/ui/dialogs/dialog_text_field_configuration.h"
+
+#include "base/logging.h"
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+@interface DialogTextFieldConfiguration ()
+
+// Initializer used by the factory method.
+- (instancetype)initWithDefaultText:(NSString*)defaultText
+                    placeholderText:(NSString*)placeholderText
+                             secure:(BOOL)secure
+                         idenfifier:(id)identifier NS_DESIGNATED_INITIALIZER;
+
+@end
+
+@implementation DialogTextFieldConfiguration
+
+@synthesize defaultText = _defaultText;
+@synthesize placeholderText = _placeholderText;
+@synthesize secure = _secure;
+@synthesize identifier = _identifier;
+
+- (instancetype)initWithDefaultText:(NSString*)defaultText
+                    placeholderText:(NSString*)placeholderText
+                             secure:(BOOL)secure
+                         idenfifier:(id)identifier {
+  DCHECK(identifier);
+  if ((self = [super init])) {
+    _defaultText = [defaultText copy];
+    _placeholderText = [placeholderText copy];
+    _secure = secure;
+    _identifier = identifier;
+  }
+  return self;
+}
+
+#pragma mark - Public
+
++ (instancetype)itemWithDefaultText:(NSString*)defaultText
+                    placeholderText:(NSString*)placeholderText
+                             secure:(BOOL)secure
+                         identifier:(id)identifier {
+  return [[[self class] alloc] initWithDefaultText:defaultText
+                                   placeholderText:placeholderText
+                                            secure:secure
+                                        idenfifier:identifier];
+}
+
+@end