[IOSTabRefactoring] Remove lastVisitedTimestamp

Remove with its users.

Bug: 898379
Change-Id: Ie5a127c17c93b811e230c19b5998d81feee81270
Reviewed-on: https://chromium-review.googlesource.com/c/1298234Reviewed-by: Eugene But <eugenebut@chromium.org>
Commit-Queue: Mohammad Refaat <mrefaat@chromium.org>
Cr-Commit-Position: refs/heads/master@{#602423}

ios/chrome/browser/tabs/tab.h

@@ -139,12 +139,6 @@ extern NSString* const kProxyPassthroughHeaderValue;
 - (void)goBack;
 - (void)goForward;
 
-// Returns the timestamp of the last time the tab is visited.
-- (double)lastVisitedTimestamp;
-
-// Updates the timestamp of the last time the tab is visited.
-- (void)updateLastVisitedTimestamp;
-
 // Called before capturing a snapshot for Tab.
 - (void)willUpdateSnapshot;
 

ios/chrome/browser/tabs/tab.mm

@@ -126,9 +126,6 @@ NSString* const kTabUrlKey = @"url";
 
   OpenInController* _openInController;
 
-  // Last visited timestamp.
-  double _lastVisitedTimestamp;
-
   // The Overscroll controller responsible for displaying the
   // overscrollActionsView above the toolbar.
   OverscrollActionsController* _overscrollActionsController;
@@ -176,8 +173,6 @@ NSString* const kTabUrlKey = @"url";
 
     _browserState =
         ios::ChromeBrowserState::FromBrowserState(webState->GetBrowserState());
-
-    [self updateLastVisitedTimestamp];
   }
   return self;
 }
@@ -347,14 +342,6 @@ NSString* const kTabUrlKey = @"url";
   }
 }
 
-- (double)lastVisitedTimestamp {
-  return _lastVisitedTimestamp;
-}
-
-- (void)updateLastVisitedTimestamp {
-  _lastVisitedTimestamp = [[NSDate date] timeIntervalSince1970];
-}
-
 - (void)willUpdateSnapshot {
   [_overscrollActionsController clear];
 }

ios/chrome/browser/tabs/tab_model_selected_tab_observer.mm

@@ -46,7 +46,6 @@
 
   if (newWebState) {
     Tab* newTab = LegacyTabHelper::GetTabForWebState(newWebState);
-    [newTab updateLastVisitedTimestamp];
 
     // Persist the session state.
     if (newTab.loadFinished)