Gracefully handle didCommitNavigation: call after didFinishNavigation:

ios/web/web_state/ui/crw_wk_navigation_states.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_WEB_WEB_STATE_UI_CRW_WK_NAVIGATION_STATES_H_
 #define IOS_WEB_WEB_STATE_UI_CRW_WK_NAVIGATION_STATES_H_
 
 #include <memory>
 
 #import <Foundation/Foundation.h>
@@ skipping 38 matching lines @@
 
 // Adds a new navigation if it was not added yet. If navigation was already
 // added then updates state for existing navigation. Updating state does not
 // affect the result of |lastAddedNavigation| method. New added navigations
 // should have WKNavigationState::REQUESTED, WKNavigationState::STARTED or
 // WKNavigationState::COMMITTED state. |navigation| will be held as a weak
 // reference and will not be retained. No-op if |navigation| is null.
 - (void)setState:(web::WKNavigationState)state
     forNavigation:(WKNavigation*)navigation;
 
+// Returns state for a given |navigation| or NONE if navigation does not exist.
+- (web::WKNavigationState)stateForNavigation:(WKNavigation*)navigation;
+
 // Removes given |navigation|. Fails if |navigation| does not exist.
 // |navigation| can be null.
 - (void)removeNavigation:(WKNavigation*)navigation;
 
 // Adds a new navigation if it was not added yet. If navigation was already
 // added then updates context for existing navigation. Updating context does not
 // affect the result of |lastAddedNavigation| method. |navigation| will be held
 // as a weak reference and will not be retained. No-op if |navigation| is null.
 - (void)setContext:(std::unique_ptr<web::NavigationContextImpl>)context
      forNavigation:(WKNavigation*)navigation;
@@ skipping 13 matching lines @@
 // is empty.
 - (web::WKNavigationState)lastAddedNavigationState;
 
 // Returns navigations that are not yet committed, finished or failed.
 // This array may contain NSNull to represent null WKNavigation.
 - (NSSet*)pendingNavigations;
 
 @end
 
 #endif  // IOS_WEB_WEB_STATE_UI_CRW_WK_NAVIGATION_STATES_H_