Implemented WebStateObserver::DidFinishNavigation(NavigationHandle*).

ios/web/public/web_state/navigation_context.h

Index: ios/web/public/web_state/navigation_context.h
diff --git a/ios/web/public/web_state/navigation_context.h b/ios/web/public/web_state/navigation_context.h
new file mode 100644
index 0000000000000000000000000000000000000000..44b48eb220c1fbfbf45d7ac15d07c50a041005fa
--- /dev/null
+++ b/ios/web/public/web_state/navigation_context.h
@@ -0,0 +1,42 @@
+// 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_PUBLIC_WEB_STATE_NAVIGATION_CONTEXT_H_
+#define IOS_WEB_PUBLIC_WEB_STATE_NAVIGATION_CONTEXT_H_
+
+class GURL;
+
+namespace web {
+
+class WebState;
+
+// Tracks information related to a single navigation. A NavigationContext is
+// provided to WebStateObserver methods to allow observers to track specific
+// navigations and their details. Observers should clear any references to a
+// NavigationContext at the time of WebStateObserver::DidFinishNavigation, just
+// before the handle is destroyed.
+class NavigationContext {
+ public:
+  // The WebState the navigation is taking place in.
+  virtual WebState* GetWebState() = 0;
+
+  // The URL the WebState is navigating to.
+  virtual const GURL& GetUrl() const = 0;
+
+  // Whether the navigation happened in the same page. Examples of same page
+  // navigations are:
+  // * reference fragment navigations
+  // * pushState/replaceState
+  // * same page history navigation
+  virtual bool IsSamePage() const = 0;
+
+  // Whether the navigation resulted in an error page.
+  virtual bool IsErrorPage() const = 0;
+
+  virtual ~NavigationContext() {}
+};
+
+}  // namespace web
+
+#endif  // IOS_WEB_PUBLIC_WEB_STATE_NAVIGATION_CONTEXT_H_