Introduced StoreKitTabHelper class

ios/chrome/browser/store_kit/store_kit_tab_helper.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_STORE_KIT_STORE_KIT_TAB_HELPER_H_
+#define IOS_CHROME_BROWSER_STORE_KIT_STORE_KIT_TAB_HELPER_H_
+
+#include "base/ios/weak_nsobject.h"
+#include "base/macros.h"
+#import "ios/chrome/browser/store_kit/store_kit_launcher.h"
+#import "ios/web/public/web_state/web_state_user_data.h"
+
+// A Tab Helper object that can open to a page on iOS App Store for a given
+// app product ID.
+class StoreKitTabHelper : public web::WebStateUserData<StoreKitTabHelper> {
+ public:
+  explicit StoreKitTabHelper(web::WebState* web_state);
+  ~StoreKitTabHelper() override;
+
+  void SetLauncher(id<StoreKitLauncher> launcher);
+  id<StoreKitLauncher> GetLauncher();
+
+  void OpenAppStore(NSString* app_id);
+
+ private:
+  base::WeakNSProtocol<id<StoreKitLauncher>> store_kit_launcher_;
+
+  DISALLOW_COPY_AND_ASSIGN(StoreKitTabHelper);
+};
+
+#endif  // IOS_CHROME_BROWSER_STORE_KIT_STORE_KIT_TAB_HELPER_H_