[ObjC ARC] Converts ios/chrome/browser/ui/tab_switcher:tab_switcher to ARC.

ios/chrome/browser/ui/tab_switcher/tab_switcher_session_cell_data.mm

 // Copyright 2015 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/ui/tab_switcher/tab_switcher_session_cell_data.h"
 #include "ios/chrome/grit/ios_strings.h"
 #include "ui/base/l10n/l10n_util.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 @implementation TabSwitcherSessionCellData
 
 @synthesize type = _type;
 @synthesize title = _title;
 @synthesize image = _image;
 
 + (instancetype)incognitoSessionCellData {
   static TabSwitcherSessionCellData* incognitoSessionCellData = nil;
   static dispatch_once_t onceToken;
   dispatch_once(&onceToken, ^{
@@ skipping 63 matching lines @@
       messageId = IDS_IOS_TAB_SWITCHER_HEADER_OTHER_DEVICES_TABS;
       break;
   }
   [self setTitle:l10n_util::GetNSString(messageId)];
   UIImage* image = [UIImage imageNamed:imageName];
   image = [image imageWithRenderingMode:UIImageRenderingModeAlwaysTemplate];
   [self setImage:image];
 }
 
 @end