Upstream Chrome on iOS source code [2/11].

ios/chrome/browser/payments/payment_request_web_state_observer.h

+// Copyright 2016 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_PAYMENTS_PAYMENT_REQUEST_WEB_STATE_OBSERVER_H_
+#define IOS_CHROME_BROWSER_PAYMENTS_PAYMENT_REQUEST_WEB_STATE_OBSERVER_H_
+
+#import <UIKit/UIKit.h>
+
+#include "ios/web/public/web_state/web_state_observer.h"
+
+@protocol PaymentRequestWebStateDelegate<NSObject>
+@optional
+- (void)pageLoadedWithStatus:(web::PageLoadCompletionStatus)loadStatus;
+
+@end
+
+class PaymentRequestWebStateObserver : public web::WebStateObserver {
+ public:
+  explicit PaymentRequestWebStateObserver(
+      id<PaymentRequestWebStateDelegate> delegate);
+  ~PaymentRequestWebStateObserver() override;
+
+  void ObserveWebState(web::WebState* web_state);
+
+ private:
+  void PageLoaded(
+      web::PageLoadCompletionStatus load_completion_status) override;
+
+  id<PaymentRequestWebStateDelegate> delegate_;
+};
+
+#endif  // IOS_CHROME_BROWSER_PAYMENTS_PAYMENT_REQUEST_WEB_STATE_OBSERVER_H_