Handle correctly start and commit of non-latest navigations.

ios/web/web_state/ui/crw_web_controller.mm

 // Copyright 2012 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.
 
 #import "ios/web/web_state/ui/crw_web_controller.h"
 
 #import <WebKit/WebKit.h>
 
 #import <objc/runtime.h>
 #include <stddef.h>
@@ skipping 598 matching lines @@
 // Updates the internal state and informs the delegate that any outstanding load
 // operations are cancelled.
 - (void)loadCancelled;
 // If YES, the page should be closed if it successfully redirects to a native
 // application, for example if a new tab redirects to the App Store.
 - (BOOL)shouldClosePageOnNativeApplicationLoad;
 // Called following navigation completion to generate final navigation lifecycle
 // events. Navigation is considered complete when the document has finished
 // loading, or when other page load mechanics are completed on a
 // non-document-changing URL change.
-- (void)didFinishNavigation;
+- (void)didFinishNavigation:(WKNavigation*)navigation;
 // Update the appropriate parts of the model and broadcast to the embedder. This
 // may be called multiple times and thus must be idempotent.
-- (void)loadCompleteWithSuccess:(BOOL)loadSuccess;
+- (void)loadCompleteWithSuccess:(BOOL)loadSuccess
+                  forNavigation:(WKNavigation*)navigation;
 // Called after URL is finished loading and _loadPhase is set to PAGE_LOADED.
 - (void)didFinishWithURL:(const GURL&)currentURL loadSuccess:(BOOL)loadSuccess;
 // Navigates forwards or backwards by |delta| pages. No-op if delta is out of
 // bounds. Reloads if delta is 0.
 // TODO(crbug.com/661316): Move this method to NavigationManager.
 - (void)goDelta:(int)delta;
 // Informs the native controller if web usage is allowed or not.
 - (void)setNativeControllerWebUsageEnabled:(BOOL)webUsageEnabled;
 // Called when web controller receives a new message from the web page.
 - (void)didReceiveScriptMessage:(WKScriptMessage*)message;
@@ skipping 116 matching lines @@
                          sourceURL:(const GURL&)sourceURL
            linkActivatedNavigation:(BOOL)linkActivatedNavigation;
 // Returns YES if the navigation action is associated with a main frame request.
 - (BOOL)isMainFrameNavigationAction:(WKNavigationAction*)action;
 // Returns whether external URL navigation action should be opened.
 - (BOOL)shouldOpenExternalURLForNavigationAction:(WKNavigationAction*)action;
 // Updates SSL status for the current navigation item based on the information
 // provided by web view.
 - (void)updateSSLStatusForCurrentNavigationItem;
 // Called when a load ends in an SSL error and certificate chain.
-- (void)handleSSLCertError:(NSError*)error;
+- (void)handleSSLCertError:(NSError*)error forNavigation:navigation;
 
 // Used in webView:didReceiveAuthenticationChallenge:completionHandler: to
 // reply with NSURLSessionAuthChallengeDisposition and credentials.
 - (void)processAuthChallenge:(NSURLAuthenticationChallenge*)challenge
          forCertAcceptPolicy:(web::CertAcceptPolicy)policy
                   certStatus:(net::CertStatus)certStatus
            completionHandler:(void (^)(NSURLSessionAuthChallengeDisposition,
                                        NSURLCredential*))completionHandler;
 // Used in webView:didReceiveAuthenticationChallenge:completionHandler: to reply
 // with NSURLSessionAuthChallengeDisposition and credentials.
@@ skipping 112 matching lines @@
             (base::DictionaryValue*)message
                                           context:(NSDictionary*)context;
 
 // Returns YES if the given |action| should be allowed to continue.
 // If this returns NO, the load should be cancelled.
 - (BOOL)shouldAllowLoadWithNavigationAction:(WKNavigationAction*)action;
 // Called when a load ends in an error.
 // TODO(stuartmorgan): Figure out if there's actually enough shared logic that
 // this makes sense. At the very least remove inMainFrame since that only makes
 // sense for UIWebView.
-- (void)handleLoadError:(NSError*)error inMainFrame:(BOOL)inMainFrame;
+- (void)handleLoadError:(NSError*)error
+            inMainFrame:(BOOL)inMainFrame
+          forNavigation:(WKNavigation*)navigation;
 
 // Handles cancelled load in WKWebView (error with NSURLErrorCancelled code).
 - (void)handleCancelledError:(NSError*)error;
 
 // Used to decide whether a load that generates errors with the
 // NSURLErrorCancelled code should be cancelled.
 - (BOOL)shouldCancelLoadForCancelledError:(NSError*)error;
 
 // Sets up WebUI for URL.
 - (void)createWebUIForURL:(const GURL&)URL;
@@ skipping 1160 matching lines @@
 
   // Update the user agent before attempting the navigation.
   web::NavigationItem* toItem = items[index].get();
   [self updateWebViewUserAgentFromUserAgentType:toItem->GetUserAgentType()];
 
   web::NavigationItem* fromItem = sessionController.currentItem;
   BOOL sameDocumentNavigation =
       [sessionController isSameDocumentNavigationBetweenItem:fromItem
                                                      andItem:toItem];
   if (sameDocumentNavigation) {
-    [sessionController goToItemAtIndex:index];
+    [sessionController goToItemAtIndex:index discardNonCommittedItems:YES];
     [self updateHTML5HistoryState];
   } else {
     [sessionController discardNonCommittedItems];
     [sessionController setPendingItemIndex:index];
 
     web::NavigationItemImpl* pendingItem = sessionController.pendingItem;
     pendingItem->SetTransitionType(ui::PageTransitionFromInt(
         pendingItem->GetTransitionType() | ui::PAGE_TRANSITION_FORWARD_BACK));
 
     [self loadCurrentURL];
   }
 }
 
 - (BOOL)isLoaded {
   return _loadPhase == web::PAGE_LOADED;
 }
 
-- (void)didFinishNavigation {
+- (void)didFinishNavigation:(WKNavigation*)navigation {
   // This can be called at multiple times after the document has loaded. Do
   // nothing if the document has already loaded.
   if (_loadPhase == web::PAGE_LOADED)
     return;
-  [self loadCompleteWithSuccess:YES];
+  [self loadCompleteWithSuccess:YES forNavigation:navigation];
 }
 
-- (void)loadCompleteWithSuccess:(BOOL)loadSuccess {
+- (void)loadCompleteWithSuccess:(BOOL)loadSuccess
+                  forNavigation:(WKNavigation*)navigation {
   [self removePlaceholderOverlay];
   // The webView may have been torn down (or replaced by a native view). Be
   // safe and do nothing if that's happened.
   if (_loadPhase != web::PAGE_LOADING)
     return;
 
   DCHECK(_webView);
 
   const GURL currentURL([self currentURL]);
 
   _loadPhase = web::PAGE_LOADED;
 
   [self optOutScrollsToTopForSubviews];
 
-  // Ensure the URL is as expected (and already reported to the delegate).
-  // If |_lastRegisteredRequestURL| is invalid then |currentURL| will be
-  // "about:blank".
-  DCHECK((currentURL == _lastRegisteredRequestURL) ||
+  DCHECK((currentURL == _lastRegisteredRequestURL) ||  // latest navigation
+         // previous navigation
+         ![[_navigationStates lastAddedNavigation] isEqual:navigation] ||
+         // invalid URL load
          (!_lastRegisteredRequestURL.is_valid() &&
           _documentURL.spec() == url::kAboutBlankURL))
       << std::endl
       << "currentURL = [" << currentURL << "]" << std::endl
       << "_lastRegisteredRequestURL = [" << _lastRegisteredRequestURL << "]";
 
   // Perform post-load-finished updates.
   [self didFinishWithURL:currentURL loadSuccess:loadSuccess];
 
   // Execute the pending LoadCompleteActions.
@@ skipping 688 matching lines @@
                   transition:transition];
 
   NSString* replaceWebViewJS =
       [self javaScriptToReplaceWebViewURL:pushURL stateObjectJSON:stateObject];
   base::WeakNSObject<CRWWebController> weakSelf(self);
   [self executeJavaScript:replaceWebViewJS completionHandler:^(id, NSError*) {
     if (!weakSelf || weakSelf.get()->_isBeingDestroyed)
       return;
     base::scoped_nsobject<CRWWebController> strongSelf([weakSelf retain]);
     [strongSelf optOutScrollsToTopForSubviews];
-    [strongSelf didFinishNavigation];
+    [strongSelf didFinishNavigation:nil];
   }];
   return YES;
 }
 
 - (BOOL)handleWindowHistoryDidReplaceStateMessage:
     (base::DictionaryValue*)message
                                           context:(NSDictionary*)context {
   DCHECK(_changingHistoryState);
   _changingHistoryState = NO;
 
@@ skipping 34 matching lines @@
   _URLOnStartLoading = replaceURL;
   _lastRegisteredRequestURL = replaceURL;
   [self replaceStateWithPageURL:replaceURL stateObject:stateObject];
   NSString* replaceStateJS = [self javaScriptToReplaceWebViewURL:replaceURL
                                                  stateObjectJSON:stateObject];
   base::WeakNSObject<CRWWebController> weakSelf(self);
   [self executeJavaScript:replaceStateJS completionHandler:^(id, NSError*) {
     if (!weakSelf || weakSelf.get()->_isBeingDestroyed)
       return;
     base::scoped_nsobject<CRWWebController> strongSelf([weakSelf retain]);
-    [strongSelf didFinishNavigation];
+    [strongSelf didFinishNavigation:nil];
   }];
   return YES;
 }
 
 #pragma mark -
 
 - (BOOL)wantsKeyboardShield {
   if ([self.nativeController
           respondsToSelector:@selector(wantsKeyboardShield)]) {
     return [self.nativeController wantsKeyboardShield];
@@ skipping 214 matching lines @@
     web::NavigationItemImpl* item = self.currentNavItem;
     // TODO(crbug.com/570699): Remove this check once it's no longer possible to
     // have no current entries.
     if (item)
       [self cachePOSTDataForRequest:request inNavigationItem:item];
   }
 
   return YES;
 }
 
-- (void)handleLoadError:(NSError*)error inMainFrame:(BOOL)inMainFrame {
+- (void)handleLoadError:(NSError*)error
+            inMainFrame:(BOOL)inMainFrame
+          forNavigation:(WKNavigation*)navigation {
   NSString* MIMEType = [_pendingNavigationInfo MIMEType];
   if ([_passKitDownloader isMIMETypePassKitType:MIMEType])
     return;
   if ([error code] == NSURLErrorUnsupportedURL)
     return;
   // In cases where a Plug-in handles the load do not take any further action.
   if ([error.domain isEqual:base::SysUTF8ToNSString(web::kWebKitErrorDomain)] &&
       (error.code == web::kWebKitErrorPlugInLoadFailed ||
        error.code == web::kWebKitErrorCannotShowUrl))
     return;
@@ skipping 42 matching lines @@
   if ([error.domain isEqual:base::SysUTF8ToNSString(web::kWebKitErrorDomain)] &&
       error.code == web::kWebKitErrorFrameLoadInterruptedByPolicyChange) {
     // See if the delegate wants to handle this case.
     if (errorGURL.is_valid() &&
         [_delegate
             respondsToSelector:@selector(
                                    controllerForUnhandledContentAtURL:)]) {
       id<CRWNativeContent> controller =
           [_delegate controllerForUnhandledContentAtURL:errorGURL];
       if (controller) {
-        [self loadCompleteWithSuccess:NO];
+        [self loadCompleteWithSuccess:NO forNavigation:navigation];
         [self removeWebViewAllowingCachedReconstruction:NO];
         [self setNativeController:controller];
         [self loadNativeViewWithSuccess:YES];
         return;
       }
     }
 
     // Ignore errors that originate from URLs that are opened in external apps.
     if ([_openedApplicationURL containsObject:errorURL])
       return;
     // Certain frame errors don't have URL information for some reason; for
     // those cases (so far the only known case is plugin content loaded directly
     // in a frame) just ignore the error. See crbug.com/414295
     if (!errorURL) {
       DCHECK(!inMainFrame);
       return;
     }
     // The wrapper error uses the URL of the error and not the requested URL
     // (which can be different in case of a redirect) to match desktop Chrome
     // behavior.
     NSError* wrapperError = [NSError
         errorWithDomain:[error domain]
                    code:[error code]
                userInfo:@{
                  NSURLErrorFailingURLStringErrorKey : [errorURL absoluteString],
                  NSUnderlyingErrorKey : error
                }];
-    [self loadCompleteWithSuccess:NO];
+    [self loadCompleteWithSuccess:NO forNavigation:navigation];
     [self loadErrorInNativeView:wrapperError];
     return;
   }
 
   if ([error code] == NSURLErrorCancelled) {
     [self handleCancelledError:error];
     // NSURLErrorCancelled errors that aren't handled by aborting the load will
     // automatically be retried by the web view, so early return in this case.
     return;
   }
 
-  [self loadCompleteWithSuccess:NO];
+  [self loadCompleteWithSuccess:NO forNavigation:navigation];
   [self loadErrorInNativeView:error];
 }
 
 - (void)handleCancelledError:(NSError*)error {
   if ([self shouldCancelLoadForCancelledError:error]) {
     [self loadCancelled];
     [[self sessionController] discardNonCommittedItems];
   }
 }
 
@@ skipping 712 matching lines @@
 
 - (void)didShowCreditCardInputOnHTTP {
   DCHECK(!web::IsOriginSecure(self.webState->GetLastCommittedURL()));
   web::NavigationItem* item =
       _webStateImpl->GetNavigationManager()->GetLastCommittedItem();
   item->GetSSL().content_status |=
       web::SSLStatus::DISPLAYED_CREDIT_CARD_FIELD_ON_HTTP;
   _webStateImpl->OnVisibleSecurityStateChange();
 }
 
-- (void)handleSSLCertError:(NSError*)error {
+- (void)handleSSLCertError:(NSError*)error
+             forNavigation:(WKNavigation*)navigation {
   CHECK(web::IsWKWebViewSSLCertError(error));
 
   net::SSLInfo info;
   web::GetSSLInfoFromWKWebViewSSLCertError(error, &info);
 
   if (!info.cert) {
     // |info.cert| can be null if certChain in NSError is empty or can not be
     // parsed, in this case do not ask delegate if error should be allowed, it
     // should not be.
-    [self handleLoadError:error inMainFrame:YES];
+    [self handleLoadError:error inMainFrame:YES forNavigation:navigation];
     return;
   }
 
   // Retrieve verification results from _certVerificationErrors cache to avoid
   // unnecessary recalculations. Verification results are cached for the leaf
   // cert, because the cert chain in |didReceiveAuthenticationChallenge:| is
   // the OS constructed chain, while |chain| is the chain from the server.
   NSArray* chain = error.userInfo[web::kNSErrorPeerCertificateChainKey];
   NSURL* requestURL = error.userInfo[web::kNSErrorFailingURLKey];
   NSString* host = [requestURL host];
@@ skipping 179 matching lines @@
   }
 
   CRWWKScriptMessageRouter* messageRouter =
       [self webViewConfigurationProvider].GetScriptMessageRouter();
 
   [_POSTRequestLoader loadPOSTRequest:request
                             inWebView:_webView
                         messageRouter:messageRouter
                     completionHandler:^(NSError* loadError) {
                       if (loadError)
-                        [self handleLoadError:loadError inMainFrame:YES];
+                        [self handleLoadError:loadError
+                                  inMainFrame:YES
+                                forNavigation:nil];
                       else
                         self.webStateImpl->SetContentsMimeType("text/html");
                     }];
 }
 
 - (void)loadHTML:(NSString*)HTML forURL:(const GURL&)URL {
   // Remove the transient content view.
   [self clearTransientContentView];
 
   _loadPhase = web::LOAD_REQUESTED;
@@ skipping 243 matching lines @@
                           : WKNavigationResponsePolicyCancel);
 }
 
 // TODO(stuartmorgan): Move all the guesswork around these states out of the
 // superclass, and wire these up to the remaining methods.
 - (void)webView:(WKWebView*)webView
     didStartProvisionalNavigation:(WKNavigation*)navigation {
   [_navigationStates setState:web::WKNavigationState::STARTED
                 forNavigation:navigation];
 
+  if (navigation &&
+      ![[_navigationStates lastAddedNavigation] isEqual:navigation]) {
+    // |navigation| is not the latest navigation and will be cancelled.
+    // Ignore |navigation| as a new navigation will start soon.
+    return;
+  }
+
   GURL webViewURL = net::GURLWithNSURL(webView.URL);
   if (webViewURL.is_empty()) {
     // May happen on iOS9, however in didCommitNavigation: callback the URL
     // will be "about:blank".
     webViewURL = GURL(url::kAboutBlankURL);
   }
 
   // Intercept renderer-initiated navigations. If this navigation has not yet
   // been registered, do so. loadPhase check is necessary because
   // lastRegisteredRequestURL may be the same as the webViewURL on a new tab
@@ skipping 67 matching lines @@
   }
 
   // Handle load cancellation for directly cancelled navigations without
   // handling their potential errors. Otherwise, handle the error.
   if ([_pendingNavigationInfo cancelled]) {
     [self loadCancelled];
   } else {
     error = WKWebViewErrorWithSource(error, PROVISIONAL_LOAD);
 
     if (web::IsWKWebViewSSLCertError(error))
-      [self handleSSLCertError:error];
+      [self handleSSLCertError:error forNavigation:navigation];
     else
-      [self handleLoadError:error inMainFrame:YES];
+      [self handleLoadError:error inMainFrame:YES forNavigation:navigation];
   }
 
   // This must be reset at the end, since code above may need information about
   // the pending load.
   _pendingNavigationInfo.reset();
   _certVerificationErrors->Clear();
 }
 
 - (void)webView:(WKWebView*)webView
     didCommitNavigation:(WKNavigation*)navigation {
   [_navigationStates setState:web::WKNavigationState::COMMITTED
                 forNavigation:navigation];
 
   DCHECK_EQ(_webView, webView);
   _certVerificationErrors->Clear();
 
   // This is the point where the document's URL has actually changed, and
   // pending navigation information should be applied to state information.
   [self setDocumentURL:net::GURLWithNSURL([_webView URL])];
 
   if (!_lastRegisteredRequestURL.is_valid() &&
       _documentURL != _lastRegisteredRequestURL) {
     // if |_lastRegisteredRequestURL| is an invalid URL, then |_documentURL|
     // will be "about:blank".
     [[self sessionController] updatePendingItem:_documentURL];
   }
-  DCHECK(_documentURL == _lastRegisteredRequestURL ||
-         (!_lastRegisteredRequestURL.is_valid() &&
+
+  // If |navigation| is nil (which happens for windows open by DOM), then it
+  // should be the first and the only pending navigaiton.
+  BOOL isLastNavigation =
+      !navigation ||
+      [[_navigationStates lastAddedNavigation] isEqual:navigation];
+  DCHECK(_documentURL == _lastRegisteredRequestURL ||  // latest navigation
+         !isLastNavigation ||                          // previous navigation
+         (!_lastRegisteredRequestURL.is_valid() &&     // invalid URL load
           _documentURL.spec() == url::kAboutBlankURL));
 
   self.webStateImpl->UpdateHttpResponseHeaders(_documentURL);
   [self commitPendingNavigationInfo];
   if ([self currentBackForwardListItemHolder]->navigation_type() ==
       WKNavigationTypeBackForward) {
     // A fast back/forward won't call decidePolicyForNavigationResponse, so
     // the MIME type needs to be updated explicitly.
     NSString* storedMIMEType =
         [self currentBackForwardListItemHolder]->mime_type();
     if (storedMIMEType) {
       self.webStateImpl->SetContentsMimeType(
           base::SysNSStringToUTF8(storedMIMEType));
     }
   }
 
   // This point should closely approximate the document object change, so reset
   // the list of injected scripts to those that are automatically injected.
   _injectedScriptManagers.reset([[NSMutableSet alloc] init]);
   if ([self contentIsHTML] || self.webState->GetContentsMimeType().empty()) {
     // In unit tests MIME type will be empty, because loadHTML:forURL: does not
     // notify web view delegate about received response, so web controller does
     // not get a chance to properly update MIME type.
     [self injectWindowID];
   }
 
-  [self webPageChanged];
+  if (isLastNavigation) {
+    [self webPageChanged];
+  } else {
+    // WKWebView has more than one in progress navigaiton, and committed

[kkhorimoto, 2017/04/19 00:34:41]

s/navigaiton/navigation

[Eugene But (OOO till 7-30), 2017/04/19 01:24:36]

Done.

+    // navigation was not the latests. It is critical to keep last committed

[kkhorimoto, 2017/04/19 00:34:41]

s/latests/latest.

[Eugene But (OOO till 7-30), 2017/04/19 01:24:36]

Done.

+    // URL the same as actual document URL, so try guessing which navigation
+    // item should be set to current.
+    // TODO(crbug.com/712269):
+    for (int i = 0; i < self.navigationManagerImpl->GetItemCount(); i++) {
+      web::NavigationItem* item = self.navigationManagerImpl->GetItemAtIndex(i);
+      if (item->GetURL() == _documentURL) {
+        // Do not discard pending entry, because another pending navigation is
+        // still in progress and will commit or fail soon.
+        [self.sessionController goToItemAtIndex:i discardNonCommittedItems:NO];
+      }
+    }
+  }
   self.webStateImpl->OnNavigationCommitted(_documentURL);
 
   [self updateSSLStatusForCurrentNavigationItem];
 
   // Attempt to update the HTML5 history state.
   [self updateHTML5HistoryState];
 
   // This is the point where pending entry has been committed, and navigation
   // item title should be updated.
   [self setNavigationItemTitle:[_webView title]];
@@ skipping 11 matching lines @@
     didFinishNavigation:(WKNavigation*)navigation {
   [_navigationStates setState:web::WKNavigationState::FINISHED
                 forNavigation:navigation];
 
   DCHECK(!_isHalted);
   // Trigger JavaScript driven post-document-load-completion tasks.
   // TODO(crbug.com/546350): Investigate using
   // WKUserScriptInjectionTimeAtDocumentEnd to inject this material at the
   // appropriate time rather than invoking here.
   web::ExecuteJavaScript(webView, @"__gCrWeb.didFinishNavigation()", nil);
-  [self didFinishNavigation];
+  [self didFinishNavigation:navigation];
 }
 
 - (void)webView:(WKWebView*)webView
     didFailNavigation:(WKNavigation*)navigation
             withError:(NSError*)error {
   [_navigationStates setState:web::WKNavigationState::FAILED
                 forNavigation:navigation];
 
   [self handleLoadError:WKWebViewErrorWithSource(error, NAVIGATION)
-            inMainFrame:YES];
+            inMainFrame:YES
+          forNavigation:navigation];
   _certVerificationErrors->Clear();
 }
 
 - (void)webView:(WKWebView*)webView
     didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge*)challenge
                     completionHandler:
                         (void (^)(NSURLSessionAuthChallengeDisposition,
                                   NSURLCredential*))completionHandler {
   NSString* authMethod = challenge.protectionSpace.authenticationMethod;
   if ([authMethod isEqual:NSURLAuthenticationMethodHTTPBasic] ||
@@ skipping 139 matching lines @@
     } else {
       _webStateImpl->OnNavigationCommitted(webViewURL);
     }
   }
 
   [self updateSSLStatusForCurrentNavigationItem];
 
   // Fast back forward navigation may not call |didFinishNavigation:|, so
   // signal did finish navigation explicitly.
   if (_lastRegisteredRequestURL == _documentURL) {
-    [self didFinishNavigation];
+    [self didFinishNavigation:nil];
   }
 }
 
 - (void)webViewTitleDidChange {
   // WKWebView's title becomes empty when the web process dies; ignore that
   // update.
   if (_webProcessIsDead) {
     DCHECK_EQ([_webView title].length, 0U);
     return;
   }
@@ skipping 126 matching lines @@
     if (![self isLoadRequestPendingForURL:newURL])
       [self registerLoadRequest:newURL];
   }
 
   [self setDocumentURL:newURL];
 
   if (!_changingHistoryState) {
     [self didStartLoadingURL:_documentURL];
     _webStateImpl->OnSameDocumentNavigation(newURL);
     [self updateSSLStatusForCurrentNavigationItem];
-    [self didFinishNavigation];
+    [self didFinishNavigation:nil];
   }
 }
 
 - (BOOL)isLoadRequestPendingForURL:(const GURL&)targetURL {
   if (self.loadPhase != web::LOAD_REQUESTED)
     return NO;
 
   web::NavigationItem* pendingItem =
       self.webState->GetNavigationManager()->GetPendingItem();
   return pendingItem && pendingItem->GetURL() == targetURL;
@@ skipping 194 matching lines @@
 - (void)simulateLoadRequestWithURL:(const GURL&)URL {
   _lastRegisteredRequestURL = URL;
   _loadPhase = web::LOAD_REQUESTED;
 }
 
 - (NSString*)referrerFromNavigationAction:(WKNavigationAction*)action {
   return [action.request valueForHTTPHeaderField:kReferrerHeaderName];
 }
 
 @end