[ios] BubbleViewController and BubbleView stubs.

ios/chrome/browser/ui/bubble_promo/bubble_view.h

+// 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_BUBBLE_PROMO_BUBBLE_VIEW_H_
+#define IOS_CHROME_BROWSER_UI_BUBBLE_PROMO_BUBBLE_VIEW_H_
+
+#import <UIKit/UIKit.h>
+
+enum class BubbleArrowDirection;
+enum class BubbleAlignment;
+
+// Speech bubble shaped view that displays a message.
+@interface BubbleView : UIView
+
+@property(nonatomic, readonly) BubbleArrowDirection arrowDirection;
+@property(nonatomic, readonly) BubbleAlignment alignment;
+
+- (instancetype)initWithText:(NSString*)text
+                   direction:(BubbleArrowDirection)arrowDirection
+                   alignment:(BubbleAlignment)alignment
+    NS_DESIGNATED_INITIALIZER;
+
+- (instancetype)initWithFrame:(CGRect)frame NS_UNAVAILABLE;
+
+- (instancetype)initWithCoder:(NSCoder*)aDecoder NS_UNAVAILABLE;
+
+- (instancetype)init NS_UNAVAILABLE;
+
+@end
+
+#endif  // IOS_CHROME_BROWSER_UI_BUBBLE_PROMO_BUBBLE_VIEW_H_