Implemented WebStateObserver::DidFinishNavigation(NavigationHandle*).

ios/web/web_state/navigation_context_impl.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_WEB_WEB_STATE_NAVIGATION_CONTEXT_IMPL_H_
+#define IOS_WEB_WEB_STATE_NAVIGATION_CONTEXT_IMPL_H_
+
+#include <memory>
+
+#include "base/macros.h"
+#include "ios/web/public/web_state/navigation_context.h"
+#include "url/gurl.h"
+
+namespace web {
+
+// Tracks information related to a single navigation.
+class NavigationContextImpl : public NavigationContext {
+ public:
+  // Creates navigation context for sucessful navigation to a different page.
+  static std::unique_ptr<NavigationContext> CreateNavigationContext(
+      WebState* web_state,
+      const GURL& url);
+
+  // Creates navigation context for sucessful same page navigation.
+  static std::unique_ptr<NavigationContext> CreateSamePageNavigationContext(
+      WebState* web_state,
+      const GURL& url);
+
+  // Creates navigation context for the error page navigation.
+  static std::unique_ptr<NavigationContext> CreateErrorPageNavigationContext(
+      WebState* web_state,
+      const GURL& url);
+
+  // NavigationContext overrides:
+  WebState* GetWebState() override;
+  const GURL& GetUrl() const override;
+  bool IsSamePage() const override;
+  bool IsErrorPage() const override;
+
+ private:
+  NavigationContextImpl(WebState* web_state,
+                        const GURL& url,
+                        bool is_same_page,
+                        bool is_error_page);
+  ~NavigationContextImpl() override;
+
+  WebState* web_state_ = nullptr;
+  GURL url_;
+  bool is_same_page_ = false;
+  bool is_error_page_ = false;
+
+  DISALLOW_COPY_AND_ASSIGN(NavigationContextImpl);
+};
+
+}  // namespace web
+
+#endif  // IOS_WEB_WEB_STATE_NAVIGATION_CONTEXT_IMPL_H_