[IOSTabRefactoring] Remove urlDisplayString from tab

This is not used at all.

Bug: 898380
Change-Id: I67a86391bb99204932f2bf3f7b680f0908d22801
Reviewed-on: https://chromium-review.googlesource.com/c/1298237Reviewed-by: Eugene But <eugenebut@chromium.org>
Commit-Queue: Mohammad Refaat <mrefaat@chromium.org>
Cr-Commit-Position: refs/heads/master@{#602442}

ios/chrome/browser/tabs/tab.h

@@ -78,8 +78,6 @@ extern NSString* const kProxyPassthroughHeaderValue;
 // The current title of the tab.
 @property(nonatomic, readonly) NSString* title;
 
-@property(nonatomic, readonly) NSString* urlDisplayString;
-
 // ID associated with this tab.
 @property(nonatomic, readonly) NSString* tabId;
 

ios/chrome/browser/tabs/tab.mm

@@ -209,13 +209,6 @@ NSString* const kTabUrlKey = @"url";
   return base::SysUTF16ToNSString(title);
 }
 
-- (NSString*)urlDisplayString {
-  base::string16 urlText = url_formatter::FormatUrl(
-      self.webState->GetVisibleURL(), url_formatter::kFormatUrlOmitNothing,
-      net::UnescapeRule::SPACES, nullptr, nullptr, nullptr);
-  return base::SysUTF16ToNSString(urlText);
-}
-
 - (NSString*)tabId {
   if (!self.webState) {
     // Tab can outlive WebState, in which case Tab is not valid anymore and