[ios] BubbleViewController and BubbleView stubs.

ios/chrome/browser/ui/bubble_promo/bubble_view_controller.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_CONTROLLER_H_
+#define IOS_CHROME_BROWSER_UI_BUBBLE_PROMO_BUBBLE_VIEW_CONTROLLER_H_
+
+#import <UIKit/UIKit.h>
+
+// Defines the direction for the bubble to point.
+enum class BubbleArrowDirection {
+  // Bubble is below the target UI element and the arrow is pointing up.
+  UP,
+  // Bubble is above the target UI element and the arrow is pointing down.
+  DOWN
+};
+
+// Alignment of the bubble relative to the arrow.
+enum class BubbleAlignment { LEADING, CENTER, TRAILING };
+
+// View controller that manages a speech bubble-shaped view, which displays a
+// message and points to the UI element of interest.
+@interface BubbleViewController : UIViewController
+
+// Initializes the bubble with the given text, arrow direction, and alignment.
+- (instancetype)initWithText:(NSString*)text
+                   direction:(BubbleArrowDirection)arrowDirection
+                   alignment:(BubbleAlignment)alignment
+    NS_DESIGNATED_INITIALIZER;
+
+- (instancetype)init NS_UNAVAILABLE;
+
+- (instancetype)initWithNibName:(NSString*)nibNameOrNil
+                         bundle:(NSBundle*)nibBundleOrNil NS_UNAVAILABLE;
+
+- (instancetype)initWithCoder:(NSCoder*)aDecoder NS_UNAVAILABLE;
+
+// Animates the bubble in with a fade-in.
+- (void)animateContentIn;
+
+// Dismisses the bubble. If |animated| is true, the bubble fades out.
+- (void)dismissAnimated:(BOOL)animated;
+
+@end
+
+#endif  // IOS_CHROME_BROWSER_UI_BUBBLE_PROMO_BUBBLE_VIEW_CONTROLLER_H_