Relanding "Fixed title updating for back forward navigation."

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 684 matching lines @@
 // TODO(stuartmorgan): Move the pushState/replaceState logic into
 // NavigationManager.
 - (void)pushStateWithPageURL:(const GURL&)pageURL
                  stateObject:(NSString*)stateObject
                   transition:(ui::PageTransition)transition;
 // Assigns the given URL and state object to the current CRWSessionEntry.
 - (void)replaceStateWithPageURL:(const GURL&)pageUrl
                     stateObject:(NSString*)stateObject;
 // Sets _documentURL to newURL, and updates any relevant state information.
 - (void)setDocumentURL:(const GURL&)newURL;
+// Sets last committed NavigationItem's title to the given |title|, which can
+// not be nil.
+- (void)setNavigationItemTitle:(NSString*)title;
 // Returns YES if the current navigation item corresponds to a web page
 // loaded by a POST request.
 - (BOOL)isCurrentNavigationItemPOST;
 // Returns YES if current navigation item is WKNavigationTypeBackForward.
 - (BOOL)isCurrentNavigationBackForward;
 // Returns whether the given navigation is triggered by a user link click.
 - (BOOL)isLinkNavigation:(WKNavigationType)navigationType;
 
 // Inject windowID if not yet injected.
 - (void)injectWindowID;
@@ skipping 646 matching lines @@
   [self didUpdateHistoryStateWithPageURL:pageUrl];
 }
 
 - (void)setDocumentURL:(const GURL&)newURL {
   if (newURL != _documentURL && newURL.is_valid()) {
     _documentURL = newURL;
     _interactionRegisteredSinceLastURLChange = NO;
   }
 }
 
+- (void)setNavigationItemTitle:(NSString*)title {
+  DCHECK(title);
+  auto& navigationManager = _webStateImpl->GetNavigationManagerImpl();
+  web::NavigationItem* item = navigationManager.GetLastCommittedItem();
+  if (!item)
+    return;
+
+  base::string16 newTitle = base::SysNSStringToUTF16(title);
+  if (item->GetTitle() == newTitle)
+    return;
+
+  item->SetTitle(newTitle);
+  // TODO(crbug.com/546218): See if this can be removed; it's not clear that
+  // other platforms send this (tab sync triggers need to be compared against
+  // upstream).
+  navigationManager.OnNavigationItemChanged();
+
+  if ([_delegate respondsToSelector:@selector(webController:titleDidChange:)]) {
+    [_delegate webController:self titleDidChange:title];
+  }
+}
+
 - (BOOL)isCurrentNavigationItemPOST {
   // |_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"];
 }
 
@@ skipping 404 matching lines @@
 }
 
 - (void)loadNativeViewWithSuccess:(BOOL)loadSuccess {
   const GURL currentURL([self currentURL]);
   [self didStartLoadingURL:currentURL updateHistory:loadSuccess];
   _loadPhase = web::PAGE_LOADED;
 
   // Perform post-load-finished updates.
   [self didFinishWithURL:currentURL loadSuccess:loadSuccess];
 
-  // Inform the embedder the title changed.
+  NSString* title = [self.nativeController title];
+  if (title)
+    [self setNavigationItemTitle:title];
+
+  // If the controller handles title change notification, route those to the
+  // delegate.
   if ([_delegate respondsToSelector:@selector(webController:titleDidChange:)]) {
-    NSString* title = [self.nativeController title];
-    // If a title is present, notify the delegate.
-    if (title)
-      [_delegate webController:self titleDidChange:title];
-    // If the controller handles title change notification, route those to the
-    // delegate.
     if ([self.nativeController respondsToSelector:@selector(setDelegate:)]) {
       [self.nativeController setDelegate:self];
     }
   }
 }
 
 - (void)loadErrorInNativeView:(NSError*)error {
   [self removeWebViewAllowingCachedReconstruction:NO];
   web::NavigationItem* item = [self currentNavItem];
   const GURL currentURL = item ? item->GetVirtualURL() : GURL::EmptyGURL();
@@ skipping 2954 matching lines @@
     [self injectWindowID];
   }
 
   [self webPageChanged];
 
   [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]];
+
   // Report cases where SSL cert is missing for a secure connection.
   if (_documentURL.SchemeIsCryptographic()) {
     scoped_refptr<net::X509Certificate> cert =
         web::CreateCertFromChain([_webView certificateChain]);
     UMA_HISTOGRAM_BOOLEAN("WebController.WKWebViewHasCertForSecureConnection",
                           static_cast<bool>(cert));
   }
 }
 
 - (void)webView:(WKWebView*)webView
@@ skipping 175 matching lines @@
 }
 
 - (void)webViewTitleDidChange {
   // WKWebView's title becomes empty when the web process dies; ignore that
   // update.
   if (_webProcessIsDead) {
     DCHECK_EQ([_webView title].length, 0U);
     return;
   }
 
-  if ([self.delegate
-          respondsToSelector:@selector(webController:titleDidChange:)]) {
-    DCHECK([_webView title]);
-    [self.delegate webController:self titleDidChange:[_webView title]];
+  bool hasPendingNavigation = web::WKNavigationState::COMMITTED <=
+                              [_navigationStates lastAddedNavigationState];
+  if (hasPendingNavigation) {
+    // Do not update the title if there is a navigation in progress because
+    // there is no way to tell if KVO change fired for new or previous page.
+    [self setNavigationItemTitle:[_webView title]];
   }
 }
 
 - (void)webViewURLDidChange {
   // TODO(stuartmorgan): Determine if there are any cases where this still
   // happens, and if so whether anything should be done when it does.
   if (![_webView URL]) {
     DVLOG(1) << "Received nil URL callback";
     return;
   }
@@ skipping 298 matching lines @@
 - (void)simulateLoadRequestWithURL:(const GURL&)URL {
   _lastRegisteredRequestURL = URL;
   _loadPhase = web::LOAD_REQUESTED;
 }
 
 - (NSString*)refererFromNavigationAction:(WKNavigationAction*)action {
   return [action.request valueForHTTPHeaderField:@"Referer"];
 }
 
 @end