Upstream Chrome on iOS source code [4/11].

ios/chrome/browser/ui/contextual_search/contextual_search_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_UI_CONTEXTUAL_SEARCH_CONTEXTUAL_SEARCH_WEB_STATE_OBSERVER_H_
+#define IOS_CHROME_BROWSER_UI_CONTEXTUAL_SEARCH_CONTEXTUAL_SEARCH_WEB_STATE_OBSERVER_H_
+
+#import <UIKit/UIKit.h>
+
+#include "ios/web/public/web_state/web_state_observer.h"
+
+@protocol ContextualSearchWebStateDelegate<NSObject>
+@optional
+- (void)webState:(web::WebState*)webState
+    navigatedWithDetails:(const web::LoadCommittedDetails&)details;
+- (void)webState:(web::WebState*)webState
+    pageLoadedWithStatus:(web::PageLoadCompletionStatus)loadStatus;
+- (void)webStateDestroyed:(web::WebState*)webState;
+
+@end
+
+class ContextualSearchWebStateObserver : public web::WebStateObserver {
+ public:
+  ContextualSearchWebStateObserver(
+      id<ContextualSearchWebStateDelegate> delegate);
+  ~ContextualSearchWebStateObserver() override;
+
+  void ObserveWebState(web::WebState* web_state);
+
+ private:
+  void NavigationItemCommitted(
+      const web::LoadCommittedDetails& load_details) override;
+  void PageLoaded(
+      web::PageLoadCompletionStatus load_completion_status) override;
+  void WebStateDestroyed() override;
+
+  id<ContextualSearchWebStateDelegate> delegate_;
+  bool loaded_;
+};
+
+#endif  // IOS_CHROME_BROWSER_UI_CONTEXTUAL_SEARCH_CONTEXTUAL_SEARCH_WEB_STATE_OBSERVER_H_