[Payment Request] Picker view + showcase integration + egtests

ios/chrome/browser/payments/payment_request_picker_row.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/payments/payment_request_picker_row.h"
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+@implementation PickerRow
+
+@synthesize label = _label;
+@synthesize value = _value;
+
+- (instancetype)initWithLabel:(NSString*)label value:(NSString*)value {
+  self = [super init];
+  if (self) {
+    _label = label;
+    _value = value;
+  }
+  return self;
+}
+
+- (NSString*)description {
+  return [NSString stringWithFormat:@"Label: %@, Value: %@", _label, _value];
+}
+
+@end