[ios] TextBadgeView interface, implementation, and unit test stubs

ios/chrome/browser/ui/reading_list/text_badge_view.h

Index: ios/chrome/browser/ui/reading_list/text_badge_view.h
diff --git a/ios/chrome/browser/ui/reading_list/text_badge_view.h b/ios/chrome/browser/ui/reading_list/text_badge_view.h
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index 0000000000000000000000000000000000000000..5179c75a14fb8a175efdbc914cbed8217df2d70c
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+++ b/ios/chrome/browser/ui/reading_list/text_badge_view.h
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+// 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_CHROME_BROWSER_UI_READING_LIST_TEXT_BADGE_VIEW_H_
+#define IOS_CHROME_BROWSER_UI_READING_LIST_TEXT_BADGE_VIEW_H_
+
+#import <UIKit/UIKit.h>
+
+// Pill-shaped view that displays white text. The view stretches to fit the
+// display text, and is hidden when the text is the empty string.
+@interface TextBadgeView : UIView
+
+// Initialize the text badge with the given frame and display text.
+- (instancetype)initWithFrame:(CGRect)frame displayText:(NSString*)text;
+
+// Display the text badge view. If |animated| is true, the badge fades in.
+- (void)presentAnimated:(BOOL)animated;
+
+@end
+
+#endif  // IOS_CHROME_BROWSER_UI_READING_LIST_TEXT_BADGE_VIEW_H_