Removed CRWSessionEntry from CRWWebController.

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 25 matching lines @@
 #include "base/strings/sys_string_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/time/time.h"
 #include "base/values.h"
 #import "ios/net/http_response_headers_util.h"
 #import "ios/net/nsurlrequest_util.h"
 #include "ios/web/history_state_util.h"
 #import "ios/web/interstitials/web_interstitial_impl.h"
 #import "ios/web/navigation/crw_session_certificate_policy_manager.h"
 #import "ios/web/navigation/crw_session_controller.h"
-#import "ios/web/navigation/crw_session_entry.h"
 #import "ios/web/navigation/navigation_item_impl.h"
 #import "ios/web/navigation/navigation_manager_impl.h"
 #include "ios/web/net/cert_host_pair.h"
 #import "ios/web/net/crw_cert_verification_controller.h"
 #import "ios/web/net/crw_ssl_status_updater.h"
 #include "ios/web/public/browser_state.h"
 #include "ios/web/public/favicon_url.h"
 #import "ios/web/public/java_script_dialog_presenter.h"
 #import "ios/web/public/navigation_item.h"
 #import "ios/web/public/navigation_manager.h"
@@ skipping 401 matching lines @@
 
 // Returns YES if the user interacted with the page recently.
 @property(nonatomic, readonly) BOOL userClickedRecently;
 
 // Whether or not desktop user agent is used for the currentItem.
 @property(nonatomic, readonly) BOOL usesDesktopUserAgent;
 
 // Facade for Mojo API.
 @property(nonatomic, readonly) web::MojoFacade* mojoFacade;
 
-// Updates Desktop User Agent and calls webWillFinishHistoryNavigationFromEntry:
-// on CRWWebDelegate. TODO(crbug.com/684098): Remove this method and inline its
-// content.
-- (void)webWillFinishHistoryNavigationFromEntry:(CRWSessionEntry*)fromEntry;
-// Recreates web view if |entry| and |fromEntry| have different value for
-// IsOverridingUserAgent() flag.
-- (void)updateDesktopUserAgentForEntry:(CRWSessionEntry*)entry
-                             fromEntry:(CRWSessionEntry*)fromEntry;
+// TODO(crbug.com/692871): Remove these functions and replace with more
+// appropriate NavigationItem getters.
+// Returns the navigation item for the current page.
+@property(nonatomic, readonly) web::NavigationItemImpl* currentNavItem;
+// Returns the current transition type.
+@property(nonatomic, readonly) ui::PageTransition currentTransition;
+// Returns the referrer for current navigation item. May be empty.
+@property(nonatomic, readonly) web::Referrer currentNavItemReferrer;
+// The HTTP headers associated with the current navigation item. These are nil
+// unless the request was a POST.
+@property(nonatomic, readonly) NSDictionary* currentHTTPHeaders;
+
 // Removes the container view from the hierarchy and resets the ivar.
 - (void)resetContainerView;
 // Called when the web page has changed document and/or URL, and so the page
 // navigation should be reported to the delegate, and internal state updated to
 // reflect the fact that the navigation has occurred.
 // TODO(stuartmorgan): The code conflates URL changes and document object
 // changes; the two need to be separated and handled differently.
 - (void)webPageChanged;
 // Resets any state that is associated with a specific document object (e.g.,
 // page interaction tracking).
 - (void)resetDocumentSpecificState;
 // Called when a page (native or web) has actually started loading (i.e., for
 // a web page the document has actually changed), or after the load request has
 // been registered for a non-document-changing URL change. Updates internal
 // state not specific to web pages, and informs the delegate.
 - (void)didStartLoadingURL:(const GURL&)URL updateHistory:(BOOL)updateHistory;
 // Returns YES if the URL looks like it is one CRWWebController can show.
 + (BOOL)webControllerCanShow:(const GURL&)url;
 // Clears the currently-displayed transient content view.
 - (void)clearTransientContentView;
 // Returns a lazily created CRWTouchTrackingRecognizer.
 - (CRWTouchTrackingRecognizer*)touchTrackingRecognizer;
 // Shows placeholder overlay.
 - (void)addPlaceholderOverlay;
 // Removes placeholder overlay.
 - (void)removePlaceholderOverlay;
 
-// Returns the current entry from the underlying session controller.
-// TODO(stuartmorgan): Audit all calls to these methods; these are just wrappers
-// around the same logic as GetActiveEntry, so should probably not be used for
-// the same reason that GetActiveEntry is deprecated. (E.g., page operations
-// should generally be dealing with the last commited entry, not a pending
-// entry).
-- (CRWSessionEntry*)currentSessionEntry;
-// Returns the navigation item for the current page.
-- (web::NavigationItem*)currentNavItem;
-// Returns the current transition type.
-- (ui::PageTransition)currentTransition;
-// Returns the referrer for current navigation item. May be empty.
-- (web::Referrer)currentSessionEntryReferrer;
-// The HTTP headers associated with the current navigation item. These are nil
-// unless the request was a POST.
-- (NSDictionary*)currentHTTPHeaders;
-
 // Creates a web view if it's not yet created.
 - (void)ensureWebViewCreated;
 // Creates a web view with given |config|. No-op if web view is already created.
 - (void)ensureWebViewCreatedWithConfiguration:(WKWebViewConfiguration*)config;
 // Returns a new autoreleased web view created with given configuration.
 - (WKWebView*)webViewWithConfiguration:(WKWebViewConfiguration*)config;
 // Sets the value of the webView property, and performs its basic setup.
 - (void)setWebView:(WKWebView*)webView;
 // Removes webView, optionally tracking the URL of the evicted
 // page for later cache-based reconstruction.
@@ skipping 71 matching lines @@
 // 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;
 // 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;
 // Loads a new URL if the current entry is not from a pushState() navigation.
-// |fromEntry| is the CRWSessionEntry that was the current entry prior to the
+// |item| is the NavigationItem that was the current entry prior to the
 // navigation.
-- (void)finishHistoryNavigationFromEntry:(CRWSessionEntry*)fromEntry;
+- (void)finishHistoryNavigationFromItem:(web::NavigationItem*)item;
 // 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;
 // Returns a new script which wraps |script| with windowID check so |script| is
 // not evaluated on windowID mismatch.
 - (NSString*)scriptByAddingWindowIDCheckForScript:(NSString*)script;
 // Attempts to handle a script message. Returns YES on success, NO otherwise.
 - (BOOL)respondToWKScriptMessage:(WKScriptMessage*)scriptMessage;
 // Registers load request with empty referrer and link or client redirect
@@ skipping 648 matching lines @@
   }
   // Any non-web URL source is trusted.
   *trustLevel = web::URLVerificationTrustLevel::kAbsolute;
   if (self.nativeController) {
     if ([self.nativeController respondsToSelector:@selector(virtualURL)]) {
       return [self.nativeController virtualURL];
     } else {
       return [self.nativeController url];
     }
   }
-  web::NavigationItem* item = [self currentNavItem];
+  web::NavigationItem* item = self.currentNavItem;
   return item ? item->GetVirtualURL() : GURL::EmptyGURL();
 }
 
 - (WKWebView*)webView {
   return _webView.get();
 }
 
 - (UIScrollView*)webScrollView {
   return [_webView scrollView];
 }
 
 - (GURL)currentURL {
   web::URLVerificationTrustLevel trustLevel =
       web::URLVerificationTrustLevel::kNone;
   return [self currentURLWithTrustLevel:&trustLevel];
 }
 
 - (web::Referrer)currentReferrer {
   // Referrer string doesn't include the fragment, so in cases where the
   // previous URL is equal to the current referrer plus the fragment the
   // previous URL is returned as current referrer.
   NSString* referrerString = _currentReferrerString;
 
   // In case of an error evaluating the JavaScript simply return empty string.
   if ([referrerString length] == 0)
     return web::Referrer();
 
-  web::NavigationItem* item = [self currentNavItem];
+  web::NavigationItem* item = self.currentNavItem;
   GURL navigationURL = item ? item->GetVirtualURL() : GURL::EmptyGURL();
   NSString* previousURLString = base::SysUTF8ToNSString(navigationURL.spec());
   // Check if the referrer is equal to the previous URL minus the hash symbol.
   // L'#' is used to convert the char '#' to a unichar.
   if ([previousURLString length] > [referrerString length] &&
       [previousURLString hasPrefix:referrerString] &&
       [previousURLString characterAtIndex:[referrerString length]] == L'#') {
     referrerString = previousURLString;
   }
   // Since referrer is being extracted from the destination page, the correct
@@ skipping 54 matching lines @@
   // |_pendingNavigationInfo| will be nil if the decidePolicy* delegate methods
   // were not called.
   NSString* HTTPMethod =
       _pendingNavigationInfo
           ? [_pendingNavigationInfo HTTPMethod]
           : [self currentBackForwardListItemHolder]->http_method();
   return [HTTPMethod isEqual:@"POST"];
 }
 
 - (BOOL)isCurrentNavigationBackForward {
-  if (![self currentNavItem])
+  if (!self.currentNavItem)
     return NO;
   WKNavigationType currentNavigationType =
       [self currentBackForwardListItemHolder]->navigation_type();
   return currentNavigationType == WKNavigationTypeBackForward;
 }
 
 - (BOOL)isLinkNavigation:(WKNavigationType)navigationType {
   switch (navigationType) {
     case WKNavigationTypeLinkActivated:
       return YES;
@@ skipping 153 matching lines @@
     // A new session history entry needs to be created.
     self.navigationManagerImpl->AddPendingItem(
         requestURL, referrer, transition,
         web::NavigationInitiationType::RENDERER_INITIATED);
   }
   _webStateImpl->SetIsLoading(true);
   _webStateImpl->OnProvisionalNavigationStarted(requestURL);
 }
 
 - (void)updateHTML5HistoryState {
-  web::NavigationItemImpl* currentItem =
-      static_cast<web::NavigationItemImpl*>([self currentNavItem]);
+  web::NavigationItemImpl* currentItem = self.currentNavItem;
   if (!currentItem)
     return;
 
   // Same-document navigations must trigger a popState event.
   CRWSessionController* sessionController = self.sessionController;
   BOOL sameDocumentNavigation = [sessionController
       isSameDocumentNavigationBetweenItem:sessionController.currentItem
                                   andItem:sessionController.previousItem];
   // WKWebView doesn't send hashchange events for same-document non-BFLI
   // navigations, so one must be dispatched manually for hash change same-
   // document navigations.
-  web::NavigationItem* previousItem =
-      self.sessionController.previousEntry.navigationItem;
   const GURL URL = currentItem->GetURL();
+  web::NavigationItem* previousItem = self.sessionController.previousItem;
   const GURL oldURL = previousItem ? previousItem->GetURL() : GURL();
   BOOL shouldDispatchHashchange = sameDocumentNavigation && previousItem &&
                                   (web::GURLByRemovingRefFromGURL(URL) ==
                                    web::GURLByRemovingRefFromGURL(oldURL));
   // The URL and state object must be set for same-document navigations and
   // NavigationItems that were created or updated by calls to pushState() or
   // replaceState().
   BOOL shouldUpdateState = sameDocumentNavigation ||
                            currentItem->IsCreatedFromPushState() ||
                            currentItem->HasStateBeenReplaced();
@@ skipping 32 matching lines @@
 
 - (NSString*)javaScriptToDispatchHashChangeWithOldURL:(const GURL&)oldURL
                                                newURL:(const GURL&)newURL {
   return [NSString
       stringWithFormat:@"__gCrWeb.dispatchHashchangeEvent(\'%s\', \'%s\');",
                        oldURL.spec().c_str(), newURL.spec().c_str()];
 }
 
 - (void)injectHTML5HistoryScriptWithHashChange:(BOOL)dispatchHashChange
                         sameDocumentNavigation:(BOOL)sameDocumentNavigation {
-  web::NavigationItemImpl* currentItem =
-      static_cast<web::NavigationItemImpl*>([self currentNavItem]);
+  web::NavigationItemImpl* currentItem = self.currentNavItem;
   if (!currentItem)
     return;
 
   const GURL URL = currentItem->GetURL();
   NSString* stateObject = currentItem->GetSerializedStateObject();
   NSMutableString* script = [NSMutableString
       stringWithString:[self javaScriptToReplaceWebViewURL:URL
                                            stateObjectJSON:stateObject]];
   if (sameDocumentNavigation) {
     [script
         appendString:[self javaScriptToDispatchPopStateWithObject:stateObject]];
   }
   if (dispatchHashChange) {
-    web::NavigationItemImpl* previousItem =
-        self.sessionController.previousEntry.navigationItemImpl;
+    web::NavigationItemImpl* previousItem = self.sessionController.previousItem;
     const GURL oldURL = previousItem ? previousItem->GetURL() : GURL();
     [script appendString:[self javaScriptToDispatchHashChangeWithOldURL:oldURL
                                                                  newURL:URL]];
   }
   base::WeakNSObject<CRWWebController> weakSelf(self);
   [self executeJavaScript:script
         completionHandler:^(id, NSError*) {
           if (!weakSelf || weakSelf.get()->_isBeingDestroyed)
             return;
           base::scoped_nsobject<CRWWebController> strongSelf([weakSelf retain]);
           strongSelf.get()->_URLOnStartLoading = URL;
           strongSelf.get()->_lastRegisteredRequestURL = URL;
         }];
 }
 
 // Load the current URL in a web view, first ensuring the web view is visible.
 - (void)loadCurrentURLInWebView {
   // Clear the set of URLs opened in external applications.
   _openedApplicationURL.reset([[NSMutableSet alloc] init]);
 
-  web::NavigationItem* item = [self currentNavItem];
+  web::NavigationItem* item = self.currentNavItem;
   GURL targetURL = item ? item->GetVirtualURL() : GURL::EmptyGURL();
   // Load the url. The UIWebView delegate callbacks take care of updating the
   // session history and UI.
   if (!targetURL.is_valid()) {
     [self didFinishWithURL:targetURL loadSuccess:NO];
     return;
   }
 
   // JavaScript should never be evaluated here. User-entered JS should be
   // evaluated via stringByEvaluatingUserJavaScriptFromString.
@@ skipping 34 matching lines @@
   if ([_pendingNavigationInfo MIMEType]) {
     self.webStateImpl->SetContentsMimeType(
         base::SysNSStringToUTF8([_pendingNavigationInfo MIMEType]));
   }
   [self updateCurrentBackForwardListItemHolder];
 
   _pendingNavigationInfo.reset();
 }
 
 - (NSMutableURLRequest*)requestForCurrentNavigationItem {
-  web::NavigationItem* item = [self currentNavItem];
+  web::NavigationItem* item = self.currentNavItem;
   const GURL currentNavigationURL =
       item ? item->GetVirtualURL() : GURL::EmptyGURL();
   NSMutableURLRequest* request = [NSMutableURLRequest
       requestWithURL:net::NSURLWithGURL(currentNavigationURL)];
-  const web::Referrer referrer([self currentSessionEntryReferrer]);
+  const web::Referrer referrer(self.currentNavItemReferrer);
   if (referrer.url.is_valid()) {
     std::string referrerValue =
         web::ReferrerHeaderValueForNavigation(currentNavigationURL, referrer);
     if (!referrerValue.empty()) {
       [request setValue:base::SysUTF8ToNSString(referrerValue)
           forHTTPHeaderField:kReferrerHeaderName];
     }
   }
 
   // If there are headers in the current session entry add them to |request|.
   // Headers that would overwrite fields already present in |request| are
   // skipped.
-  NSDictionary* headers = [self currentHTTPHeaders];
+  NSDictionary* headers = self.currentHTTPHeaders;
   for (NSString* headerName in headers) {
     if (![request valueForHTTPHeaderField:headerName]) {
       [request setValue:[headers objectForKey:headerName]
           forHTTPHeaderField:headerName];
     }
   }
 
   return request;
 }
 
 - (web::WKBackForwardListItemHolder*)currentBackForwardListItemHolder {
-  web::NavigationItem* item = [self currentSessionEntry].navigationItemImpl;
+  web::NavigationItem* item = self.currentNavItem;
   DCHECK(item);
   web::WKBackForwardListItemHolder* holder =
       web::WKBackForwardListItemHolder::FromNavigationItem(item);
   DCHECK(holder);
   return holder;
 }
 
 - (void)updateCurrentBackForwardListItemHolder {
   // WebUI pages (which are loaded via loadHTMLString:baseURL:) have no entry
   // in the back/forward list, so the current item will still be the previous
@@ skipping 37 matching lines @@
     [self setNavigationItemTitle:title];
   }
 
   if ([self.nativeController respondsToSelector:@selector(setDelegate:)]) {
     [self.nativeController setDelegate:self];
   }
 }
 
 - (void)loadErrorInNativeView:(NSError*)error {
   [self removeWebViewAllowingCachedReconstruction:NO];
-  web::NavigationItem* item = [self currentNavItem];
+  web::NavigationItem* item = self.currentNavItem;
   const GURL currentURL = item ? item->GetVirtualURL() : GURL::EmptyGURL();
 
   if (web::IsWKWebViewSSLCertError(error)) {
     // This could happen only if certificate is absent or could not be parsed.
     error = web::NetErrorFromError(error, net::ERR_SSL_SERVER_CERT_BAD_FORMAT);
 #if defined(DEBUG)
     net::SSLInfo info;
     web::GetSSLInfoFromWKWebViewSSLCertError(error, &info);
     CHECK(!error.cert);
 #endif
   } else {
     error = web::NetErrorFromError(error);
   }
 
   BOOL isPost = [self isCurrentNavigationItemPOST];
   [self setNativeController:[_nativeProvider controllerForURL:currentURL
                                                     withError:error
                                                        isPost:isPost]];
   [self loadNativeViewWithSuccess:NO];
 }
 
 // Load the current URL in a native controller, retrieved from the native
 // provider. Call |loadNativeViewWithSuccess:YES| to load the native controller.
 - (void)loadCurrentURLInNativeView {
   // Free the web view.
   [self removeWebViewAllowingCachedReconstruction:NO];
 
-  web::NavigationItem* item = [self currentNavItem];
+  web::NavigationItem* item = self.currentNavItem;
   const GURL targetURL = item ? item->GetURL() : GURL::EmptyGURL();
   const web::Referrer referrer;
   id<CRWNativeContent> nativeContent =
       [_nativeProvider controllerForURL:targetURL webState:self.webState];
   // Unlike the WebView case, always create a new controller and view.
   // TODO(pinkerton): What to do if this does return nil?
   [self setNativeController:nativeContent];
   if ([nativeContent respondsToSelector:@selector(virtualURL)]) {
     item->SetVirtualURL([nativeContent virtualURL]);
   }
 
   [self registerLoadRequest:targetURL
                    referrer:referrer
-                 transition:[self currentTransition]];
+                 transition:self.currentTransition];
   [self loadNativeViewWithSuccess:YES];
 }
 
 - (void)loadWithParams:(const NavigationManager::WebLoadParams&)originalParams {
   // Make a copy of |params|, as some of the delegate methods may modify it.
   NavigationManager::WebLoadParams params(originalParams);
 
   // Initiating a navigation from the UI, record the current page state before
   // the new page loads. Don't record for back/forward, as the current entry
   // has already been moved to the next entry in the history. Do, however,
@@ skipping 18 matching lines @@
   } else {
     // Clear transient view before making any changes to history and navigation
     // manager. TODO(stuartmorgan): Drive Transient Item clearing from
     // navigation system, rather than from WebController.
     [self clearTransientContentView];
 
     // TODO(stuartmorgan): Why doesn't recordStateInHistory get called for
     // forward/back transitions?
     [self recordStateInHistory];
 
-    if (!self.currentSessionEntry)
+    if (!self.currentNavItem)
       initialNavigation = YES;
 
     web::NavigationInitiationType navigationInitiationType =
         params.is_renderer_initiated
             ? web::NavigationInitiationType::RENDERER_INITIATED
             : web::NavigationInitiationType::USER_INITIATED;
     self.navigationManagerImpl->AddPendingItem(
         navUrl, params.referrer, transition, navigationInitiationType);
 
-    web::NavigationItemImpl* addedItem =
-        [self currentSessionEntry].navigationItemImpl;
+    web::NavigationItemImpl* addedItem = self.currentNavItem;
     DCHECK(addedItem);
     if (params.extra_headers)
       addedItem->AddHttpRequestHeaders(params.extra_headers);
     if (params.post_data) {
       DCHECK([addedItem->GetHttpRequestHeaders() objectForKey:@"Content-Type"])
           << "Post data should have an associated content type";
       addedItem->SetPostData(params.post_data);
       addedItem->SetShouldSkipRepostFormConfirmation(true);
     }
   }
@@ skipping 15 matching lines @@
 
   // Abort any outstanding page load. This ensures the delegate gets informed
   // about the outgoing page, and further messages from the page are suppressed.
   if (_loadPhase != web::PAGE_LOADED)
     [self abortLoad];
 
   DCHECK(!_isHalted);
   // Remove the transient content view.
   [self clearTransientContentView];
 
-  web::NavigationItem* item = [self currentNavItem];
+  web::NavigationItem* item = self.currentNavItem;
   const GURL currentURL = item ? item->GetURL() : GURL::EmptyGURL();
   // If it's a chrome URL, but not a native one, create the WebUI instance.
   if (web::GetWebClient()->IsAppSpecificURL(currentURL) &&
       ![_nativeProvider hasControllerForURL:currentURL]) {
     if (!(item->GetTransitionType() & ui::PAGE_TRANSITION_TYPED ||
           item->GetTransitionType() & ui::PAGE_TRANSITION_AUTO_BOOKMARK) &&
         self.sessionController.openedByDOM) {
       // WebUI URLs can not be opened by DOM to prevent cross-site scripting as
       // they have increased power. WebUI URLs may only be opened when the user
       // types in the URL or use bookmarks.
@@ skipping 52 matching lines @@
     _containerView.get().frame = containerViewFrame;
     DCHECK(!CGRectIsEmpty(_containerView.get().frame));
 
     // TODO(crbug.com/691116): Remove this workaround once tests are no longer
     // dependent upon this accessibility ID.
     if (!base::ios::IsRunningOnIOS10OrLater())
       [_containerView setAccessibilityIdentifier:@"Container View"];
 
     [_containerView addGestureRecognizer:[self touchTrackingRecognizer]];
     // Is |currentUrl| a web scheme or native chrome scheme.
-    web::NavigationItem* item = [self currentNavItem];
+    web::NavigationItem* item = self.currentNavItem;
     const GURL currentNavigationURL =
         item ? item->GetVirtualURL() : GURL::EmptyGURL();
     BOOL isChromeScheme =
         web::GetWebClient()->IsAppSpecificURL(currentNavigationURL);
 
     // Don't immediately load the web page if in overlay mode. Always load if
     // native.
     if (isChromeScheme || !_overlayPreviewMode) {
       // TODO(jimblackler): end the practice of calling |loadCurrentURL| when it
       // is possible there is no current URL. If the call performs necessary
@@ skipping 93 matching lines @@
       }
       [_delegate webLoadCancelled:_URLOnStartLoading];
       break;
     case web::PAGE_LOADED:
       break;
   }
 }
 
 - (void)goToItemAtIndex:(int)index {
   CRWSessionController* sessionController = self.sessionController;
-  NSArray* entries = sessionController.entries;
-  if (index < 0 || index >= static_cast<int>(entries.count)) {
+  web::NavigationItemList items = sessionController.items;
+  if (index < 0 || index >= static_cast<int>(items.size())) {
     NOTREACHED();
     return;
   }
 
   if (!_webStateImpl->IsShowingWebInterstitial())
     [self recordStateInHistory];
-  CRWSessionEntry* fromEntry = sessionController.currentEntry;
-  CRWSessionEntry* toEntry = entries[index];
+  web::NavigationItem* fromItem = sessionController.currentItem;
+  web::NavigationItem* toItem = items[index];
 
   NSUserDefaults* userDefaults = [NSUserDefaults standardUserDefaults];
   if (![userDefaults boolForKey:@"PendingIndexNavigationDisabled"]) {
     [self clearTransientContentView];
-    [self updateDesktopUserAgentForEntry:toEntry fromEntry:fromEntry];
 
-    BOOL sameDocumentNavigation = [sessionController
-        isSameDocumentNavigationBetweenItem:fromEntry.navigationItem
-                                    andItem:toEntry.navigationItem];
+    // Require page reconstruction if the navigation changes the user agent.
+    if (fromItem->IsOverridingUserAgent() != toItem->IsOverridingUserAgent()) {
+      [self requirePageReconstruction];
+    }
+
+    BOOL sameDocumentNavigation =
+        [sessionController isSameDocumentNavigationBetweenItem:fromItem
+                                                       andItem:toItem];
     if (sameDocumentNavigation) {
       [sessionController goToItemAtIndex:index];
       [self updateHTML5HistoryState];
     } else {
       [sessionController discardNonCommittedItems];
       [sessionController setPendingItemIndex:index];
 
-      web::NavigationItemImpl* pendingItem =
-          sessionController.pendingEntry.navigationItemImpl;
+      web::NavigationItemImpl* pendingItem = sessionController.pendingItem;
       pendingItem->SetTransitionType(ui::PageTransitionFromInt(
           pendingItem->GetTransitionType() | ui::PAGE_TRANSITION_FORWARD_BACK));
 
       [self loadCurrentURL];
     }
   } else {
     [sessionController goToItemAtIndex:index];
-    if (fromEntry)
-      [self finishHistoryNavigationFromEntry:fromEntry];
+    if (fromItem)
+      [self finishHistoryNavigationFromItem:fromItem];
   }
 }
 
 - (BOOL)isLoaded {
   return _loadPhase == web::PAGE_LOADED;
 }
 
 - (void)didFinishNavigation {
   // This can be called at multiple times after the document has loaded. Do
   // nothing if the document has already loaded.
@@ skipping 43 matching lines @@
   // WKWebView will cache the WebUI HTML in the previous WKBackForwardListItem
   // since it's loaded via |-loadHTML:forURL:| instead of an NSURLRequest.  As a
   // result, the WebUI's HTML and URL will be loaded when navigating to that
   // WKBackForwardListItem, causing a mismatch between the visible content and
   // the visible URL (WebUI page will be visible, but URL will be the previous
   // page's URL).  To prevent this potential URL spoofing vulnerability, reset
   // the previous NavigationItem's WKBackForwardListItem to force loading via
   // NSURLRequest.
   if (_webUIManager) {
     web::NavigationItem* lastNavigationItem =
-        self.sessionController.previousEntry.navigationItem;
+        self.sessionController.previousItem;
     if (lastNavigationItem) {
       web::WKBackForwardListItemHolder* holder =
           web::WKBackForwardListItemHolder::FromNavigationItem(
               lastNavigationItem);
       DCHECK(holder);
       holder->set_back_forward_list_item(nil);
     }
   }
 
   [self restoreStateFromHistory];
   _webStateImpl->SetIsLoading(false);
   _webStateImpl->OnPageLoaded(currentURL, loadSuccess);
 }
 
 - (void)goDelta:(int)delta {
   if (_isBeingDestroyed)
     return;
 
   if (delta == 0) {
     [self reload];
     return;
   }
 
   if (self.navigationManagerImpl->CanGoToOffset(delta)) {
     NSInteger index = self.navigationManagerImpl->GetIndexForOffset(delta);
     [self goToItemAtIndex:index];
   }
 }
 
-- (void)finishHistoryNavigationFromEntry:(CRWSessionEntry*)fromEntry {
-  [self webWillFinishHistoryNavigationFromEntry:fromEntry];
+- (void)finishHistoryNavigationFromItem:(web::NavigationItem*)item {
+  // Require page reconstruction if the navigation changes the user agent.
+  web::NavigationItemImpl* currentItem = self.currentNavItem;
+  if (currentItem->IsOverridingUserAgent() != item->IsOverridingUserAgent()) {
+    [self requirePageReconstruction];
+  }
 
   // Only load the new URL if it has a different document than |fromEntry| to
   // prevent extra page loads from NavigationItems created by hash changes or
   // calls to window.history.pushState().
   BOOL shouldLoadURL = ![self.sessionController
-      isSameDocumentNavigationBetweenItem:fromEntry.navigationItem
+      isSameDocumentNavigationBetweenItem:item
                                   andItem:self.currentNavItem];
-  web::NavigationItemImpl* currentItem =
-      self.currentSessionEntry.navigationItemImpl;
-  GURL endURL = [self URLForHistoryNavigationFromItem:fromEntry.navigationItem
-                                               toItem:currentItem];
+  GURL endURL = [self URLForHistoryNavigationFromItem:item toItem:currentItem];
   if (shouldLoadURL) {
     ui::PageTransition transition = ui::PageTransitionFromInt(
         ui::PAGE_TRANSITION_RELOAD | ui::PAGE_TRANSITION_FORWARD_BACK);
 
     NavigationManager::WebLoadParams params(endURL);
     if (currentItem) {
       params.referrer = currentItem->GetReferrer();
     }
     params.transition_type = transition;
     [self loadWithParams:params];
@@ skipping 49 matching lines @@
   // no user interaction with the page since the web view was created, or if
   // the page has no navigation items, as occurs when an App Store link is
   // opened from another application.
   BOOL rendererInitiatedWithoutInteraction =
       self.sessionController.openedByDOM && !_userInteractedWithWebController;
   BOOL noNavigationItems = !(self.navigationManagerImpl->GetItemCount());
   return rendererInitiatedWithoutInteraction || noNavigationItems;
 }
 
 - (BOOL)usesDesktopUserAgent {
-  web::NavigationItem* item = [self currentNavItem];
+  web::NavigationItem* item = self.currentNavItem;
   return item && item->IsOverridingUserAgent();
 }
 
 - (web::MojoFacade*)mojoFacade {
   if (!_mojoFacade) {
     service_manager::mojom::InterfaceProvider* interfaceProvider =
         _webStateImpl->GetMojoInterfaceRegistry();
     _mojoFacade.reset(new web::MojoFacade(interfaceProvider, self));
   }
   return _mojoFacade.get();
@@ skipping 19 matching lines @@
       [delegate webController:strongSelf didLoadPassKitObject:data];
     }
   };
   web::BrowserState* browserState = self.webStateImpl->GetBrowserState();
   _passKitDownloader.reset([[CRWPassKitDownloader alloc]
       initWithContextGetter:browserState->GetRequestContext()
           completionHandler:passKitCompletion]);
   return _passKitDownloader.get();
 }
 
-- (void)webWillFinishHistoryNavigationFromEntry:(CRWSessionEntry*)fromEntry {
-  DCHECK(fromEntry);
-  [self updateDesktopUserAgentForEntry:self.currentSessionEntry
-                             fromEntry:fromEntry];
-  [_delegate webWillFinishHistoryNavigationFromEntry:fromEntry];
-}
-
-- (void)updateDesktopUserAgentForEntry:(CRWSessionEntry*)entry
-                             fromEntry:(CRWSessionEntry*)fromEntry {
-  web::NavigationItemImpl* item = entry.navigationItemImpl;
-  web::NavigationItemImpl* fromItem = fromEntry.navigationItemImpl;
-  if (!item || !fromItem)
-    return;
-  bool useDesktopUserAgent = item->IsOverridingUserAgent();
-  if (useDesktopUserAgent != fromItem->IsOverridingUserAgent()) {
-    [self requirePageReconstruction];
-  }
-}
-
 #pragma mark -
 #pragma mark CRWWebControllerContainerViewDelegate
 
 - (CRWWebViewProxyImpl*)contentViewProxyForContainerView:
         (CRWWebControllerContainerView*)containerView {
   return _webViewProxy.get();
 }
 
 - (CGFloat)headerHeightForContainerView:
         (CRWWebControllerContainerView*)containerView {
@@ skipping 427 matching lines @@
   // for the new page manually.
   [self executeJavaScript:@"__gCrWeb.sendFaviconsToHost();"
         completionHandler:nil];
 
   // Record that the current NavigationItem was created by a hash change, but
   // ignore hashchange events that are manually dispatched for same-document
   // navigations.
   if (_dispatchingSameDocumentHashChangeEvent) {
     _dispatchingSameDocumentHashChangeEvent = NO;
   } else {
-    web::NavigationItemImpl* item =
-        static_cast<web::NavigationItemImpl*>([self currentNavItem]);
+    web::NavigationItemImpl* item = self.currentNavItem;
     DCHECK(item);
     item->SetIsCreatedFromHashChange(true);
   }
 
   return YES;
 }
 
 - (BOOL)handleWindowHistoryBackMessage:(base::DictionaryValue*)message
                                context:(NSDictionary*)context {
   [self goDelta:-1];
@@ skipping 25 matching lines @@
 - (BOOL)handleWindowHistoryDidPushStateMessage:(base::DictionaryValue*)message
                                        context:(NSDictionary*)context {
   DCHECK(_changingHistoryState);
   _changingHistoryState = NO;
 
   // If there is a pending entry, a new navigation has been registered but
   // hasn't begun loading.  Since the pushState message is coming from the
   // previous page, ignore it and allow the previously registered navigation to
   // continue.  This can ocur if a pushState is issued from an anchor tag
   // onClick event, as the click would have already been registered.
-  if ([self sessionController].pendingEntry)
+  if ([self sessionController].pendingItem)
     return NO;
 
   std::string pageURL;
   std::string baseURL;
   if (!message->GetString("pageUrl", &pageURL) ||
       !message->GetString("baseUrl", &baseURL)) {
     DLOG(WARNING) << "JS message parameter not found: pageUrl or baseUrl";
     return NO;
   }
   GURL pushURL = web::history_state_util::GetHistoryStateChangeUrl(
       [self currentURL], GURL(baseURL), pageURL);
   // UIWebView seems to choke on unicode characters that haven't been
   // escaped; escape the URL now so the expected load URL is correct.
   pushURL = URLEscapedForHistory(pushURL);
   if (!pushURL.is_valid())
     return YES;
-  web::NavigationItem* navItem = [self currentNavItem];
+  web::NavigationItem* navItem = self.currentNavItem;
   // PushState happened before first navigation entry or called when the
   // navigation entry does not contain a valid URL.
   if (!navItem || !navItem->GetURL().is_valid())
     return YES;
   if (!web::history_state_util::IsHistoryStateChangeValid(
-          [self currentNavItem]->GetURL(), pushURL)) {
+          self.currentNavItem->GetURL(), pushURL)) {
     // If the current session entry URL origin still doesn't match pushURL's
     // origin, ignore the pushState. This can happen if a new URL is loaded
     // just before the pushState.
     return YES;
   }
   std::string stateObjectJSON;
   if (!message->GetString("stateObject", &stateObjectJSON)) {
     DLOG(WARNING) << "JS message parameter not found: stateObject";
     return NO;
   }
@@ skipping 39 matching lines @@
     return NO;
   }
   GURL replaceURL = web::history_state_util::GetHistoryStateChangeUrl(
       [self currentURL], GURL(baseURL), pageURL);
   // UIWebView seems to choke on unicode characters that haven't been
   // escaped; escape the URL now so the expected load URL is correct.
   replaceURL = URLEscapedForHistory(replaceURL);
   if (!replaceURL.is_valid())
     return YES;
 
-  web::NavigationItem* navItem = [self currentNavItem];
+  web::NavigationItem* navItem = self.currentNavItem;
   // ReplaceState happened before first navigation entry or called right
   // after window.open when the url is empty/not valid.
   if (!navItem || (self.navigationManagerImpl->GetItemCount() <= 1 &&
                    navItem->GetURL().is_empty()))
     return YES;
   if (!web::history_state_util::IsHistoryStateChangeValid(
-          [self currentNavItem]->GetURL(), replaceURL)) {
+          self.currentNavItem->GetURL(), replaceURL)) {
     // If the current session entry URL origin still doesn't match
     // replaceURL's origin, ignore the replaceState. This can happen if a
     // new URL is loaded just before the replaceState.
     return YES;
   }
   std::string stateObjectJSON;
   if (!message->GetString("stateObject", &stateObjectJSON)) {
     DLOG(WARNING) << "JS message parameter not found: stateObject";
     return NO;
   }
@@ skipping 35 matching lines @@
 // we should be distinguishing better, and be clear about the expected
 // WebDelegate and WCO callbacks in each case.
 - (void)webPageChanged {
   DCHECK(_loadPhase == web::LOAD_REQUESTED);
 
   const GURL currentURL([self currentURL]);
   web::Referrer referrer = [self currentReferrer];
   // If no referrer was known in advance, record it now. (If there was one,
   // keep it since it will have a more accurate URL and policy than what can
   // be extracted from the landing page.)
-  web::NavigationItem* currentItem = [self currentNavItem];
+  web::NavigationItem* currentItem = self.currentNavItem;
   if (!currentItem->GetReferrer().url.is_valid()) {
     currentItem->SetReferrer(referrer);
   }
 
   // TODO(stuartmorgan): This shouldn't be called for hash state or
   // push/replaceState.
   [self resetDocumentSpecificState];
 
   [self didStartLoadingURL:currentURL updateHistory:YES];
 }
@@ skipping 39 matching lines @@
   _userInteractionRegistered = flag;
   if (flag)
     _interactionRegisteredSinceLastURLChange = YES;
 }
 
 - (BOOL)userInteractionRegistered {
   return _userInteractionRegistered;
 }
 
 - (void)cachePOSTDataForRequest:(NSURLRequest*)request
-                 inSessionEntry:(CRWSessionEntry*)currentSessionEntry {
+               inNavigationItem:(web::NavigationItemImpl*)item {
   NSUInteger maxPOSTDataSizeInBytes = 4096;
   NSString* cookieHeaderName = @"cookie";
 
-  web::NavigationItemImpl* currentItem = currentSessionEntry.navigationItemImpl;
-  DCHECK(currentItem);
+  DCHECK(item);
   const bool shouldUpdateEntry =
-      ui::PageTransitionCoreTypeIs(currentItem->GetTransitionType(),
+      ui::PageTransitionCoreTypeIs(item->GetTransitionType(),
                                    ui::PAGE_TRANSITION_FORM_SUBMIT) &&
       ![request HTTPBodyStream] &&  // Don't cache streams.
-      !currentItem->HasPostData() &&
-      currentItem->GetURL() == net::GURLWithNSURL([request URL]);
+      !item->HasPostData() &&
+      item->GetURL() == net::GURLWithNSURL([request URL]);
   const bool belowSizeCap =
       [[request HTTPBody] length] < maxPOSTDataSizeInBytes;
   DLOG_IF(WARNING, shouldUpdateEntry && !belowSizeCap)
       << "Data in POST request exceeds the size cap (" << maxPOSTDataSizeInBytes
       << " bytes), and will not be cached.";
 
   if (shouldUpdateEntry && belowSizeCap) {
-    currentItem->SetPostData([request HTTPBody]);
-    currentItem->ResetHttpRequestHeaders();
-    currentItem->AddHttpRequestHeaders([request allHTTPHeaderFields]);
+    item->SetPostData([request HTTPBody]);
+    item->ResetHttpRequestHeaders();
+    item->AddHttpRequestHeaders([request allHTTPHeaderFields]);
     // Don't cache the "Cookie" header.
     // According to NSURLRequest documentation, |-valueForHTTPHeaderField:| is
     // case insensitive, so it's enough to test the lower case only.
     if ([request valueForHTTPHeaderField:cookieHeaderName]) {
       // Case insensitive search in |headers|.
-      NSSet* cookieKeys = [currentItem->GetHttpRequestHeaders()
+      NSSet* cookieKeys = [item->GetHttpRequestHeaders()
           keysOfEntriesPassingTest:^(id key, id obj, BOOL* stop) {
             NSString* header = (NSString*)key;
             const BOOL found =
                 [header caseInsensitiveCompare:cookieHeaderName] ==
                 NSOrderedSame;
             *stop = found;
             return found;
           }];
       DCHECK_EQ(1u, [cookieKeys count]);
-      currentItem->RemoveHttpRequestHeaderForKey([cookieKeys anyObject]);
+      item->RemoveHttpRequestHeaderForKey([cookieKeys anyObject]);
     }
   }
 }
 
 // TODO(stuartmorgan): This is mostly logic from the original UIWebView delegate
 // method, which provides less information than the WKWebView version. Audit
 // this for things that should be handled in the subclass instead.
 - (BOOL)shouldAllowLoadWithNavigationAction:(WKNavigationAction*)action {
   NSURLRequest* request = action.request;
   GURL requestURL = net::GURLWithNSURL(request.URL);
 
   // External application launcher needs |isNavigationTypeLinkActivated| to
   // decide if the user intended to open the application by clicking on a link.
   BOOL isNavigationTypeLinkActivated =
       action.navigationType == WKNavigationTypeLinkActivated;
 
   // Check if the link navigation leads to a launch of an external app.
   // TODO(crbug.com/607780): Revise the logic of allowing external app launch
   // and move it to externalAppLauncher.
   BOOL isOpenInNewTabNavigation = !(self.navigationManagerImpl->GetItemCount());
   BOOL isPossibleLinkClick = [self isLinkNavigation:action.navigationType];
   if (isPossibleLinkClick || isOpenInNewTabNavigation ||
-      PageTransitionCoreTypeIs([self currentTransition],
+      PageTransitionCoreTypeIs(self.currentTransition,
                                ui::PAGE_TRANSITION_AUTO_BOOKMARK)) {
-    web::NavigationItem* item = [self currentNavItem];
+    web::NavigationItem* item = self.currentNavItem;
     const GURL currentNavigationURL =
         item ? item->GetVirtualURL() : GURL::EmptyGURL();
     // Check If the URL is handled by a native app.
     if ([self urlTriggersNativeAppLaunch:requestURL
                                sourceURL:currentNavigationURL
                  linkActivatedNavigation:isNavigationTypeLinkActivated]) {
       // External app has been launched successfully. Stop the current page
       // load operation (e.g. notifying all observers) and record the URL so
       // that errors reported following the 'NO' reply can be safely ignored.
       if ([self shouldClosePageOnNativeApplicationLoad])
@@ skipping 47 matching lines @@
       // Record the URL so that errors reported following the 'NO' reply can be
       // safely ignored.
       [_openedApplicationURL addObject:request.URL];
       if ([self shouldClosePageOnNativeApplicationLoad])
         [_delegate webPageOrderedClose];
     }
     return NO;
   }
 
   if ([[request HTTPMethod] isEqualToString:@"POST"]) {
-    CRWSessionEntry* currentEntry = [self currentSessionEntry];
+    web::NavigationItemImpl* item = self.currentNavItem;
     // TODO(crbug.com/570699): Remove this check once it's no longer possible to
     // have no current entries.
-    if (currentEntry)
-      [self cachePOSTDataForRequest:request inSessionEntry:currentEntry];
+    if (item)
+      [self cachePOSTDataForRequest:request inNavigationItem:item];
   }
 
   return YES;
 }
 
 - (void)handleLoadError:(NSError*)error inMainFrame:(BOOL)inMainFrame {
   NSString* MIMEType = [_pendingNavigationInfo MIMEType];
   if ([_passKitDownloader isMIMETypePassKitType:MIMEType])
     return;
   if ([error code] == NSURLErrorUnsupportedURL)
@@ skipping 366 matching lines @@
 
 - (CRWSessionController*)sessionController {
   NavigationManagerImpl* navigationManager = self.navigationManagerImpl;
   return navigationManager ? navigationManager->GetSessionController() : nil;
 }
 
 - (NavigationManagerImpl*)navigationManagerImpl {
   return _webStateImpl ? &(_webStateImpl->GetNavigationManagerImpl()) : nil;
 }
 
-- (CRWSessionEntry*)currentSessionEntry {
-  return [[self sessionController] currentEntry];
-}
-
-- (web::NavigationItem*)currentNavItem {
+- (web::NavigationItemImpl*)currentNavItem {
   // This goes through the legacy Session* interface rather than Navigation*
   // because it is itself a legacy method that should not exist, and this
   // avoids needing to add a GetActiveItem to NavigationManager. If/when this
   // method chain becomes a blocker to eliminating SessionController, the logic
   // can be moved here, using public NavigationManager getters. That's not
   // done now in order to avoid code duplication.
-  return [[self currentSessionEntry] navigationItem];
+  return [[self sessionController] currentItem];
 }
 
 - (ui::PageTransition)currentTransition {
-  if ([self currentNavItem])
-    return [self currentNavItem]->GetTransitionType();
+  if (self.currentNavItem)
+    return self.currentNavItem->GetTransitionType();
   else
     return ui::PageTransitionFromInt(0);
 }
 
-- (web::Referrer)currentSessionEntryReferrer {
-  web::NavigationItem* currentItem = [self currentNavItem];
+- (web::Referrer)currentNavItemReferrer {
+  web::NavigationItem* currentItem = self.currentNavItem;
   return currentItem ? currentItem->GetReferrer() : web::Referrer();
 }
 
 - (NSDictionary*)currentHTTPHeaders {
-  DCHECK([self currentSessionEntry]);
-  return [self currentSessionEntry].navigationItem->GetHttpRequestHeaders();
+  web::NavigationItem* currentItem = self.currentNavItem;
+  return currentItem ? currentItem->GetHttpRequestHeaders() : nil;
 }
 
 #pragma mark -
 #pragma mark CRWWebViewScrollViewProxyObserver
 
 - (void)webViewScrollViewDidZoom:
         (CRWWebViewScrollViewProxy*)webViewScrollViewProxy {
   _pageHasZoomed = YES;
 
   base::WeakNSObject<UIScrollView> weakScrollView(self.webScrollView);
   [self extractViewportTagWithCompletion:^(
             const web::PageViewportState* viewportState) {
     if (!weakScrollView)
       return;
     base::scoped_nsobject<UIScrollView> scrollView([weakScrollView retain]);
     if (viewportState && !viewportState->viewport_tag_present() &&
         [scrollView minimumZoomScale] == [scrollView maximumZoomScale] &&
         [scrollView zoomScale] > 1.0) {
       UMA_HISTOGRAM_BOOLEAN(kUMAViewportZoomBugCount, true);
     }
   }];
 }
 
 - (void)webViewScrollViewDidResetContentSize:
     (CRWWebViewScrollViewProxy*)webViewScrollViewProxy {
-  web::NavigationItem* currentItem = [self currentNavItem];
+  web::NavigationItem* currentItem = self.currentNavItem;
   if (webViewScrollViewProxy.isZooming || _applyingPageState || !currentItem)
     return;
   CGSize contentSize = webViewScrollViewProxy.contentSize;
   if (contentSize.width < CGRectGetWidth(webViewScrollViewProxy.frame)) {
     // The renderer incorrectly resized the content area.  Resetting the scroll
     // view's zoom scale will force a re-rendering.  rdar://23963992
     _applyingPageState = YES;
     web::PageZoomState zoomState =
         currentItem->GetPageDisplayState().zoom_state();
     if (!zoomState.IsValid())
@@ skipping 24 matching lines @@
         completionHandler:nil];
 }
 
 #pragma mark -
 #pragma mark Page State
 
 - (void)recordStateInHistory {
   // Only record the state if:
   // - the current NavigationItem's URL matches the current URL, and
   // - the user has interacted with the page.
-  CRWSessionEntry* current = [self currentSessionEntry];
-  if (current && [current navigationItem]->GetURL() == [self currentURL] &&
+  web::NavigationItem* item = self.currentNavItem;
+  if (item && item->GetURL() == [self currentURL] &&
       self.userInteractionRegistered) {
-    [current navigationItem]->SetPageDisplayState(self.pageDisplayState);
+    item->SetPageDisplayState(self.pageDisplayState);
   }
 }
 
 - (void)restoreStateFromHistory {
-  CRWSessionEntry* current = [self currentSessionEntry];
-  if ([current navigationItem])
-    self.pageDisplayState = [current navigationItem]->GetPageDisplayState();
+  web::NavigationItem* item = self.currentNavItem;
+  if (item)
+    self.pageDisplayState = item->GetPageDisplayState();
 }
 
 - (web::PageDisplayState)pageDisplayState {
   web::PageDisplayState displayState;
   if (_webView) {
     CGPoint scrollOffset = [self scrollPosition];
     displayState.scroll_state().set_offset_x(std::floor(scrollOffset.x));
     displayState.scroll_state().set_offset_y(std::floor(scrollOffset.y));
     UIScrollView* scrollView = self.webScrollView;
     displayState.zoom_state().set_minimum_zoom_scale(
@@ skipping 20 matching lines @@
         currentPageDisplayState.scroll_state().offset_y() ==
             _displayStateOnStartLoading.scroll_state().offset_y() &&
         !_pageHasZoomed) {
       [self applyPageDisplayState:displayState];
     }
   }
 }
 
 - (void)extractViewportTagWithCompletion:(ViewportStateCompletion)completion {
   DCHECK(completion);
-  web::NavigationItem* currentItem = [self currentNavItem];
+  web::NavigationItem* currentItem = self.currentNavItem;
   if (!currentItem) {
     completion(nullptr);
     return;
   }
   NSString* const kViewportContentQuery =
       @"var viewport = document.querySelector('meta[name=\"viewport\"]');"
        "viewport ? viewport.content : '';";
   base::WeakNSObject<CRWWebController> weakSelf(self);
   int itemID = currentItem->GetUniqueID();
   [self executeJavaScript:kViewportContentQuery
@@ skipping 52 matching lines @@
                          userScalable:viewportState->user_scalable()];
     }
   }];
 }
 
 - (void)applyPageDisplayState:(const web::PageDisplayState&)displayState
                  userScalable:(BOOL)isUserScalable {
   // Early return if |scrollState| doesn't match the current NavigationItem.
   // This can sometimes occur in tests, as navigation occurs programmatically
   // and |-applyPageScrollState:| is asynchronous.
-  web::NavigationItem* currentItem = [self currentSessionEntry].navigationItem;
+  web::NavigationItem* currentItem = self.currentNavItem;
   if (currentItem && currentItem->GetPageDisplayState() != displayState)
     return;
   DCHECK(displayState.IsValid());
   _applyingPageState = YES;
   if (isUserScalable) {
     [self prepareToApplyWebViewScrollZoomScale];
     [self applyWebViewScrollZoomScaleFromZoomState:displayState.zoom_state()];
     [self finishApplyingWebViewScrollZoomScale];
   }
   [self applyWebViewScrollOffsetFromScrollState:displayState.scroll_state()];
@@ skipping 392 matching lines @@
   _injectedScriptManagers.reset([[NSMutableSet alloc] init]);
   [self setDocumentURL:_defaultURL];
 }
 
 - (void)removeWebViewAllowingCachedReconstruction:(BOOL)allowCache {
   if (!_webView)
     return;
 
   _webStateImpl->CancelDialogs();
 
-  web::NavigationItem* item = [self currentNavItem];
+  web::NavigationItem* item = self.currentNavItem;
   if (allowCache && item) {
     _expectedReconstructionURL = item->GetVirtualURL();
   } else {
     _expectedReconstructionURL = GURL::EmptyGURL();
   }
 
   [self abortLoad];
   [_webView removeFromSuperview];
   [_containerView resetContent];
   [self setWebView:nil];
@@ skipping 61 matching lines @@
 }
 
 - (void)stopLoading {
   _stoppedWKNavigation.reset([_navigationStates lastAddedNavigation]);
 
   base::RecordAction(UserMetricsAction("Stop"));
   // Discard the pending and transient entried before notifying the tab model
   // observers of the change via |-abortLoad|.
   [[self sessionController] discardNonCommittedItems];
   [self abortLoad];
-  web::NavigationItem* item = [self currentNavItem];
+  web::NavigationItem* item = self.currentNavItem;
   GURL navigationURL = item ? item->GetVirtualURL() : GURL::EmptyGURL();
   // If discarding the non-committed entries results in an app-specific URL,
   // reload it in its native view.
   if (!self.nativeController &&
       [self shouldLoadURLInNativeView:navigationURL]) {
     [self loadCurrentURLInNativeView];
   }
 }
 
 #pragma mark -
@@ skipping 703 matching lines @@
   if (self.loadPhase != web::LOAD_REQUESTED)
     return NO;
 
   web::NavigationItem* pendingItem =
       self.webState->GetNavigationManager()->GetPendingItem();
   return pendingItem && pendingItem->GetURL() == targetURL;
 }
 
 - (void)loadRequestForCurrentNavigationItem {
   DCHECK(_webView && !self.nativeController);
-  DCHECK([self currentSessionEntry]);
+  DCHECK(self.currentNavItem);
   // If a load is kicked off on a WKWebView with a frame whose size is {0, 0} or
   // that has a negative dimension for a size, rendering issues occur that
   // manifest in erroneous scrolling and tap handling (crbug.com/574996,
   // crbug.com/577793).
   DCHECK_GT(CGRectGetWidth([_webView frame]), 0.0);
   DCHECK_GT(CGRectGetHeight([_webView frame]), 0.0);
 
   web::WKBackForwardListItemHolder* holder =
       [self currentBackForwardListItemHolder];
   BOOL repostedForm =
       [holder->http_method() isEqual:@"POST"] &&
       (holder->navigation_type() == WKNavigationTypeFormResubmitted ||
        holder->navigation_type() == WKNavigationTypeFormSubmitted);
-  web::NavigationItemImpl* currentItem =
-      [self currentSessionEntry].navigationItemImpl;
+  web::NavigationItemImpl* currentItem = self.currentNavItem;
   NSData* POSTData = currentItem->GetPostData();
   NSMutableURLRequest* request = [self requestForCurrentNavigationItem];
 
   // If the request has POST data and is not a repost form, configure and
   // run the POST request.
   if (POSTData.length && !repostedForm) {
     [request setHTTPMethod:@"POST"];
     [request setHTTPBody:POSTData];
-    [request setAllHTTPHeaderFields:[self currentHTTPHeaders]];
+    [request setAllHTTPHeaderFields:self.currentHTTPHeaders];
     GURL navigationURL =
         currentItem ? currentItem->GetURL() : GURL::EmptyGURL();
     [self registerLoadRequest:navigationURL
-                     referrer:[self currentSessionEntryReferrer]
-                   transition:[self currentTransition]];
+                     referrer:self.currentNavItemReferrer
+                   transition:self.currentTransition];
     [self loadPOSTRequest:request];
     return;
   }
 
   ProceduralBlock defaultNavigationBlock = ^{
-    web::NavigationItem* item = [self currentNavItem];
+    web::NavigationItem* item = self.currentNavItem;
     GURL navigationURL = item ? item->GetURL() : GURL::EmptyGURL();
     [self registerLoadRequest:navigationURL
-                     referrer:[self currentSessionEntryReferrer]
-                   transition:[self currentTransition]];
+                     referrer:self.currentNavItemReferrer
+                   transition:self.currentTransition];
     [self loadRequest:request];
   };
 
   // When navigating via WKBackForwardListItem to pages created or updated by
   // calls to pushState() and replaceState(), sometimes core.js is not injected
   // correctly.  This means that calling window.history navigation functions
   // will invoke WKWebView's non-overridden implementations, causing a mismatch
   // between the WKBackForwardList and NavigationManager.
   // TODO(crbug.com/659816): Figure out how to prevent core.js injection flake.
   if (currentItem->HasStateBeenReplaced() ||
@@ skipping 10 matching lines @@
       ![self isBackForwardListItemValid:holder->back_forward_list_item()]) {
     defaultNavigationBlock();
     return;
   }
 
   ProceduralBlock webViewNavigationBlock = ^{
     // If the current navigation URL is the same as the URL of the visible
     // page, that means the user requested a reload. |goToBackForwardListItem|
     // will be a no-op when it is passed the current back forward list item,
     // so |reload| must be explicitly called.
-    web::NavigationItem* item = [self currentNavItem];
+    web::NavigationItem* item = self.currentNavItem;
     GURL navigationURL = item ? item->GetURL() : GURL::EmptyGURL();
     [self registerLoadRequest:navigationURL
-                     referrer:[self currentSessionEntryReferrer]
-                   transition:[self currentTransition]];
+                     referrer:self.currentNavItemReferrer
+                   transition:self.currentTransition];
     if (navigationURL == net::GURLWithNSURL([_webView URL])) {
       [_navigationStates setState:web::WKNavigationState::REQUESTED
                     forNavigation:[_webView reload]];
     } else {
       // |didCommitNavigation:| may not be called for fast navigation, so update
       // the navigation type now as it is already known.
       holder->set_navigation_type(WKNavigationTypeBackForward);
       WKNavigation* navigation =
           [_webView goToBackForwardListItem:holder->back_forward_list_item()];
       [_navigationStates setState:web::WKNavigationState::REQUESTED
@@ skipping 79 matching lines @@
 - (void)simulateLoadRequestWithURL:(const GURL&)URL {
   _lastRegisteredRequestURL = URL;
   _loadPhase = web::LOAD_REQUESTED;
 }
 
 - (NSString*)referrerFromNavigationAction:(WKNavigationAction*)action {
   return [action.request valueForHTTPHeaderField:kReferrerHeaderName];
 }
 
 @end