[iOS Clean] Added dialogs UI support.

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

Index: ios/clean/chrome/browser/ui/dialogs/dialog_text_field_configuration.h
diff --git a/ios/clean/chrome/browser/ui/dialogs/dialog_text_field_configuration.h b/ios/clean/chrome/browser/ui/dialogs/dialog_text_field_configuration.h
new file mode 100644
index 0000000000000000000000000000000000000000..d88fa5c636a65ff0af5180c513cb8bb510cc9349
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+++ b/ios/clean/chrome/browser/ui/dialogs/dialog_text_field_configuration.h
@@ -0,0 +1,37 @@
+// 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.
+
+#ifndef IOS_CLEAN_CHROME_BROWSER_UI_DIALOGS_DIALOG_TEXT_FIELD_CONFIGURATION_H_
+#define IOS_CLEAN_CHROME_BROWSER_UI_DIALOGS_DIALOG_TEXT_FIELD_CONFIGURATION_H_
+
+#import <Foundation/Foundation.h>
+
+// An object encapsulating the data necessary to set up a dialog's text field.
+@interface DialogTextFieldConfiguration : NSObject
+
+// Factory method for item creation.
++ (instancetype)itemWithDefaultText:(NSString*)defaultText
+                    placeholderText:(NSString*)placeholderText
+                             secure:(BOOL)secure
+                         identifier:(id)identifier;
+
+// DialogTextFieldConfigurations should be created through the factory method.
+- (instancetype)init NS_UNAVAILABLE;
+
+// The default text to display in the text field, if any.
+@property(nonatomic, readonly, copy) NSString* defaultText;
+
+// The placehodler text to display in the text field, if any.
+@property(nonatomic, readonly, copy) NSString* placeholderText;
+
+// Whether the text field should be secure (e.g. for password).
+@property(nonatomic, readonly, getter=isSecure) BOOL secure;
+
+// The ID passed to the factory method.  This can be used to identify the text
+// fields for DialogDismissalCommands.
+@property(nonatomic, readonly, strong) id identifier;
+
+@end
+
+#endif  // IOS_CLEAN_CHROME_BROWSER_UI_DIALOGS_DIALOG_TEXT_FIELD_CONFIGURATION_H_