[ios] BubbleViewController and BubbleView stubs.

ios/chrome/browser/ui/bubble_promo/bubble_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/chrome/browser/ui/bubble_promo/bubble_configuration.h"
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+@implementation BubbleConfiguration
+
+@synthesize displayText = _displayText;
+@synthesize alignment = _alignment;
+@synthesize arrowDirection = _arrowDirection;
+@synthesize elementView = _elementView;
+@synthesize bubbleSuperview = _bubbleSuperview;
+@synthesize sourceRect = _sourceRect;
+
+- (instancetype)initWithBubbleSuperview:(UIView*)bubbleSuperview {
+  self = [super init];
+  return self;
+}
+
+@end