Refactor SecurityStateModel/Clients for simplicity and reusability.

ios/chrome/browser/ssl/ios_security_state_tab_helper.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_SSL_IOS_SECURITY_STATE_TAB_HELPER_H_
+#define IOS_CHROME_BROWSER_SSL_IOS_SECURITY_STATE_TAB_HELPER_H_
+
+#include <memory>
+
+#include "base/macros.h"
+#include "ios/web/public/web_state/web_state_user_data.h"
+
+namespace security_state {
+struct SecurityInfo;
+struct VisibleSecurityState;
+}  // namespace security_state
+
+namespace web {
+class WebState;
+}  // namespace web
+
+// Tab helper that provides the page's security status. Uses a WebState to
+// provide a security_state::GetSecurityInfo() with the relevant
+// VisibleSecurityState information.
+class IOSSecurityStateTabHelper
+    : public web::WebStateUserData<IOSSecurityStateTabHelper> {
+ public:
+  ~IOSSecurityStateTabHelper() override;
+
+  void GetSecurityInfo(security_state::SecurityInfo* result) const;
+
+ private:
+  explicit IOSSecurityStateTabHelper(web::WebState* web_state);
+  friend class web::WebStateUserData<IOSSecurityStateTabHelper>;
+
+  std::unique_ptr<security_state::VisibleSecurityState>
+  GetVisibleSecurityState() const;
+
+  web::WebState* web_state_;
+
+  DISALLOW_COPY_AND_ASSIGN(IOSSecurityStateTabHelper);
+};
+
+#endif  // IOS_CHROME_BROWSER_SSL_IOS_SECURITY_STATE_TAB_HELPER_H_