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

ios/chrome/browser/ui/history/history_panel_view_controller.mm

 // Copyright 2016 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/history/history_panel_view_controller.h"
 
 #include "base/ios/block_types.h"
 #include "base/ios/ios_util.h"
 #include "base/ios/weak_nsobject.h"
 #include "base/mac/scoped_nsobject.h"
 #include "base/metrics/user_metrics.h"
 #include "base/metrics/user_metrics_action.h"
 #include "components/strings/grit/components_strings.h"
 #import "ios/chrome/browser/ui/history/clear_browsing_bar.h"
 #import "ios/chrome/browser/ui/history/history_collection_view_controller.h"
 #import "ios/chrome/browser/ui/history/history_search_view_controller.h"
 #import "ios/chrome/browser/ui/icons/chrome_icon.h"
 #import "ios/chrome/browser/ui/keyboard/UIKeyCommand+Chrome.h"
 #import "ios/chrome/browser/ui/material_components/utils.h"
 #import "ios/chrome/browser/ui/ntp/recent_tabs/views/panel_bar_view.h"
 #import "ios/chrome/browser/ui/show_privacy_settings_util.h"
 #import "ios/chrome/browser/ui/uikit_ui_util.h"
 #import "ios/chrome/browser/ui/url_loader.h"
 #include "ios/chrome/grit/ios_strings.h"
 #import "ios/third_party/material_components_ios/src/components/AppBar/src/MaterialAppBar.h"
 #import "ios/third_party/material_components_ios/src/components/NavigationBar/src/MaterialNavigationBar.h"
 #include "ui/base/l10n/l10n_util_mac.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace {
 // Shadow opacity for the clear browsing button and the header when scrolling.
 CGFloat kShadowOpacity = 0.2f;
 }  // namespace
 
 @interface HistoryPanelViewController ()<
     HistoryCollectionViewControllerDelegate,
     HistorySearchViewControllerDelegate> {
   // Controller for collection view that displays history entries.
   base::scoped_nsobject<HistoryCollectionViewController>
@@ skipping 68 matching lines @@
 
 - (instancetype)initWithCoder:(NSCoder*)aDecoder {
   NOTREACHED();
   return nil;
 }
 
 + (UIViewController*)controllerToPresentForBrowserState:
                          (ios::ChromeBrowserState*)browserState
                                                  loader:(id<UrlLoader>)loader {
   HistoryPanelViewController* historyPanelController =
-      [[[HistoryPanelViewController alloc] initWithLoader:loader
-                                             browserState:browserState]
-          autorelease];
+      [[HistoryPanelViewController alloc] initWithLoader:loader
+                                            browserState:browserState];
   return historyPanelController;
 }
 
 - (void)viewDidLoad {
   [super viewDidLoad];
   [self setTitle:l10n_util::GetNSString(IDS_HISTORY_TITLE)];
 
   _containerView.reset([[UIView alloc] initWithFrame:self.view.frame]);
   [_containerView setAutoresizingMask:UIViewAutoresizingFlexibleWidth |
                                       UIViewAutoresizingFlexibleHeight];
@@ skipping 16 matching lines @@
   [_clearBrowsingBar setTranslatesAutoresizingMaskIntoConstraints:NO];
   [_containerView addSubview:_clearBrowsingBar];
   [self configureClearBrowsingBar];
 
   ConfigureAppBarWithCardStyle(_appBar);
   [_appBar headerViewController].headerView.trackingScrollView =
       [_historyCollectionController collectionView];
   [_appBar addSubviewsToParent];
 
   // Add navigation bar buttons.
-  _leftBarButtonItem.reset([[ChromeIcon
+  _leftBarButtonItem.reset([ChromeIcon
       templateBarButtonItemWithImage:[ChromeIcon searchIcon]
                               target:self
-                              action:@selector(enterSearchMode)] retain]);
+                              action:@selector(enterSearchMode)]);
   self.navigationItem.leftBarButtonItem = _leftBarButtonItem;
   _rightBarButtonItem.reset([[UIBarButtonItem alloc]
       initWithTitle:l10n_util::GetNSString(IDS_IOS_NAVIGATION_BAR_DONE_BUTTON)
               style:UIBarButtonItemStylePlain
              target:self
              action:@selector(closeHistory)]);
   self.navigationItem.rightBarButtonItem = _rightBarButtonItem;
   [self configureNavigationBar];
 }
 
@@ skipping 238 matching lines @@
   base::WeakNSObject<HistoryPanelViewController> weakSelf(self);
   return @[ [UIKeyCommand cr_keyCommandWithInput:UIKeyInputEscape
                                    modifierFlags:Cr_UIKeyModifierNone
                                            title:nil
                                           action:^{
                                             [weakSelf closeHistory];
                                           }] ];
 }
 
 @end