Use custom user data to serialize Tab last visited timestamp.

ios/chrome/browser/tabs/tab.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/chrome/browser/tabs/tab.h"
 
 #import <CoreLocation/CoreLocation.h>
 #import <UIKit/UIKit.h>
 
 #include <utility>
@@ skipping 168 matching lines @@
 NSString* const kTabIDKey = @"TabID";
 
 // The key under which the opener Tab ID is stored in the WebState's
 // serializable user data.
 NSString* const kOpenerIDKey = @"OpenerID";
 
 // The key under which the opener navigation index is stored in the WebState's
 // serializable user data.
 NSString* const kOpenerNavigationIndexKey = @"OpenerNavigationIndex";
 
+// The key under which the last visited timestamp is stored in the WebState's
+// serializable user data.
+NSString* const kLastVisitedTimestampKey = @"LastVisitedTimestamp";
+
 // Name of histogram for recording the state of the tab when the renderer is
 // terminated.
 const char kRendererTerminationStateHistogram[] =
     "Tab.StateAtRendererTermination";
 
 // Referrer used for clicks on article suggestions on the NTP.
 const char kChromeContentSuggestionsReferrer[] =
     "https://www.googleapis.com/auth/chrome-content-suggestions";
 
 // Enum corresponding to UMA's TabForegroundState, for
@@ skipping 335 matching lines @@
   if (self) {
     propertyReleaser_Tab_.Init(self, [Tab class]);
     tabHistoryContext_.reset(new TabHistoryContext());
     parentTabModel_ = parentModel;
     browserState_ =
         ios::ChromeBrowserState::FromBrowserState(webState->GetBrowserState());
 
     webStateImpl_.reset(static_cast<web::WebStateImpl*>(webState.release()));
     webStateObserver_.reset(
         new web::WebStateObserverBridge(webStateImpl_.get(), self));
+    [self updateLastVisitedTimestamp];
 
     // Do not respect |attachTabHelpers| as this tab helper is required for
     // proper conversion from WebState to Tab.
     LegacyTabHelper::CreateForWebState(webStateImpl_.get(), self);
 
     [self.webController setDelegate:self];
 
     NSString* sessionID = self.tabId;
     DCHECK(sessionID);
     snapshotManager_.reset([[SnapshotManager alloc] init]);
@@ skipping 1315 matching lines @@
                 linkClicked:linkClicked]) {
     return YES;
   }
 
   // Auto-open didn't work. Reset the auto-open flag.
   [metadata unsetShouldAutoOpenLinks];
   return NO;
 }
 
 - (double)lastVisitedTimestamp {
-  DCHECK([self navigationManager]);
-  return [[self navigationManagerImpl]->GetSessionController()
-              lastVisitedTimestamp];
+  DCHECK(self.webState);
+  web::SerializableUserDataManager* userDataManager =
+      web::SerializableUserDataManager::FromWebState(self.webState);
+  id<NSCoding> lastVisitedTimestamp =
+      userDataManager->GetValueForSerializationKey(kLastVisitedTimestampKey);
+  return lastVisitedTimestamp
+             ? base::mac::ObjCCastStrict<NSNumber>(lastVisitedTimestamp)
+                   .doubleValue
+             : 0.;
 }
 
 - (void)updateLastVisitedTimestamp {
-  // Stores this information in self.history and it will be written into disc
-  // with other information when needed.
-  DCHECK([self navigationManager]);
-  [[self navigationManagerImpl]->GetSessionController()
-      setLastVisitedTimestamp:[[NSDate date] timeIntervalSince1970]];
+  DCHECK(self.webState);
+  web::SerializableUserDataManager* userDataManager =
+      web::SerializableUserDataManager::FromWebState(self.webState);
+  userDataManager->AddSerializableData(@([[NSDate date] timeIntervalSince1970]),
+                                       kLastVisitedTimestampKey);
 }
 
 - (infobars::InfoBarManager*)infoBarManager {
   DCHECK(self.webState);
   return InfoBarManagerImpl::FromWebState(self.webState);
 }
 
 - (NSArray*)snapshotOverlays {
   return [snapshotOverlayProvider_ snapshotOverlaysForTab:self];
 }
@@ skipping 334 matching lines @@
 
 - (TabModel*)parentTabModel {
   return parentTabModel_;
 }
 
 - (FormInputAccessoryViewController*)inputAccessoryViewController {
   return inputAccessoryViewController_.get();
 }
 
 @end