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

ios/chrome/browser/ui/reader_mode/reader_mode_view.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/reader_mode/reader_mode_view.h"
 
-#include "base/mac/objc_property_releaser.h"
-#include "base/mac/scoped_nsobject.h"
 #include "ios/chrome/browser/dom_distiller/distiller_viewer.h"
 #import "ios/chrome/browser/ui/material_components/activity_indicator.h"
 #import "ios/third_party/material_components_ios/src/components/ActivityIndicator/src/MaterialActivityIndicator.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace {
 const CGFloat kCloseButtonSize = 40;
 const CGFloat kCloseButtonMargin = 10;
 const CGFloat kMinWidth = kCloseButtonSize + kCloseButtonMargin * 2;
 const CGFloat kMinHeight = kMinWidth;
 }  // namespace
 
 @interface ReaderModeView ()<MDCActivityIndicatorDelegate> {
   std::unique_ptr<dom_distiller::DistillerViewer> _viewer;
-  base::mac::ObjCPropertyReleaser _propertyReleaser_ReaderModeView;
 }
-@property(nonatomic, retain) MDCActivityIndicator* activityIndicator;
+@property(nonatomic, strong) MDCActivityIndicator* activityIndicator;
 @property(nonatomic, copy) ProceduralBlock animateOutCompletionBlock;
-@property(nonatomic, retain) UIButton* closeButton;
+@property(nonatomic, strong) UIButton* closeButton;
 
 @end
 
 @implementation ReaderModeView
 @synthesize activityIndicator = _activityIndicator;
 @synthesize animateOutCompletionBlock = _animateOutCompletionBlock;
 @synthesize closeButton = _closeButton;
 @synthesize delegate = _delegate;
 
 - (instancetype)initWithFrame:(CGRect)frame
                      delegate:(id<ReaderModeViewDelegate>)delegate {
   self = [super initWithFrame:frame];
   if (self) {
-    _propertyReleaser_ReaderModeView.Init(self, [ReaderModeView class]);
     _delegate = delegate;
 
     self.backgroundColor = [UIColor whiteColor];
 
     self.autoresizingMask =
         UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
 
-    _closeButton = [[UIButton buttonWithType:UIButtonTypeRoundedRect] retain];
+    _closeButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
     [_closeButton addTarget:self
                      action:@selector(close)
            forControlEvents:UIControlEventTouchUpInside];
     [_closeButton setTitle:@"X" forState:UIControlStateNormal];
     _closeButton.autoresizingMask = UIViewAutoresizingFlexibleLeftMargin |
                                     UIViewAutoresizingFlexibleTopMargin;
 
     _activityIndicator =
         [[MDCActivityIndicator alloc] initWithFrame:CGRectMake(0, 0, 24, 24)];
     _activityIndicator.delegate = self;
@@ skipping 69 matching lines @@
 - (void)activityIndicatorAnimationDidFinish:
     (MDCActivityIndicator*)activityIndicator {
   [self.activityIndicator removeFromSuperview];
   self.activityIndicator = nil;
   if (self.animateOutCompletionBlock)
     self.animateOutCompletionBlock();
   self.animateOutCompletionBlock = nil;
 }
 
 @end