LabelObserver is no longer retained by the label

ios/chrome/browser/ui/util/label_link_controller.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/util/label_link_controller.h"
 
 #include <map>
 #include <vector>
 
 #include "base/ios/ios_util.h"
@@ skipping 115 matching lines @@
 // If there are tap buttons, but they are not subviews of |_label|'s superview
 // (if _label's superview has changed since the buttons were created), then
 // the tap buttons are migrated into the new superview.
 - (void)updateTapButtons;
 
 @end
 
 @implementation LabelLinkController {
   // Ivars immutable for the lifetime of the object.
   base::mac::ScopedBlock<ProceduralBlockWithURL> _action;
-  base::WeakNSObject<UILabel> _label;  // weak
+  base::scoped_nsobject<UILabel> _label;
   base::scoped_nsobject<UITapGestureRecognizer> _linkTapRecognizer;
 
   // Ivas backing properties.
   base::scoped_nsobject<UIColor> _linkColor;
   base::scoped_nsobject<UIFont> _linkFont;
 
   // Ivars that reset when label text changes.
   base::scoped_nsobject<NSMutableDictionary> _layoutsForURLs;
   base::scoped_nsobject<NSAttributedString> _originalLabelText;
   CGRect _lastLabelFrame;
 
   // Ivars that reset when text or bounds change.
   base::scoped_nsprotocol<id<TextRegionMapper>> _textMapper;
 
   // Internal tracking.
   BOOL _justUpdatedStyles;
   base::scoped_nsobject<NSMutableArray> _linkButtons;
+  base::scoped_nsobject<LabelObserver> _labelObserver;
 }
 
 @synthesize showTapAreas = _showTapAreas;
 @synthesize textMapperClass = _textMapperClass;
 @synthesize linkUnderlineStyle = _linkUnderlineStyle;
 
 - (instancetype)initWithLabel:(UILabel*)label
                        action:(ProceduralBlockWithURL)action {
   if ((self = [super init])) {
     DCHECK(label);
-    _label.reset(label);
+    _label.reset([label retain]);
     _action.reset(action, base::scoped_policy::RETAIN);
     _linkUnderlineStyle = NSUnderlineStyleNone;
     [self reset];
 
+    _labelObserver.reset([[LabelObserver observerForLabel:_label] retain]);
+    [_labelObserver startObserving];
     [self addLabelObserverActions];
 
     self.textMapperClass = [CoreTextRegionMapper class];
     _linkButtons.reset([[NSMutableArray alloc] init]);
   }
   return self;
 }
 
 - (NSAttributedString*)originalLabelText {
   return _originalLabelText.get();
 }
 
 - (NSArray*)linkButtons {
   return _linkButtons.get();
 }
 
 - (void)addLabelObserverActions {
-  LabelObserver* observer = [LabelObserver observerForLabel:_label];
   base::WeakNSObject<LabelLinkController> weakSelf(self);
-  [observer addStyleChangedAction:^(UILabel* label) {
+  [_labelObserver addStyleChangedAction:^(UILabel* label) {
     // One of the style properties has been changed, which will silently
     // update the label's attributedText.
     if (!weakSelf)
       return;
     base::scoped_nsobject<LabelLinkController> strongSelf([weakSelf retain]);
     [strongSelf labelStyleInvalidated];
   }];
-  [observer addTextChangedAction:^(UILabel* label) {
+  [_labelObserver addTextChangedAction:^(UILabel* label) {
     if (!weakSelf)
       return;
     base::scoped_nsobject<LabelLinkController> strongSelf([weakSelf retain]);
     NSString* originalText = [[strongSelf originalLabelText] string];
     if ([label.text isEqualToString:originalText]) {
       // The actual text of the label didn't change, so this was a change to
       // the string attributes only.
       [strongSelf labelStyleInvalidated];
     } else {
       // The label text has changed, so start everything from scratch.
       [strongSelf reset];
     }
   }];
-  [observer addLayoutChangedAction:^(UILabel* label) {
+  [_labelObserver addLayoutChangedAction:^(UILabel* label) {
     if (!weakSelf)
       return;
     base::scoped_nsobject<LabelLinkController> strongSelf([weakSelf retain]);
     [strongSelf labelLayoutInvalidated];
     NSArray* linkButtons = [strongSelf linkButtons];
     // If this layout change corresponds to |label|'s moving to a new superview,
     // update the tap buttons so that they are inserted above |label| in the new
     // hierarchy.
     if (linkButtons.count && label.superview != [linkButtons[0] superview])
       [strongSelf updateTapButtons];
   }];
 }
 
 - (void)dealloc {
   [self clearTapButtons];
+  [_labelObserver stopObserving];
   [super dealloc];
 }
 
 - (void)addLinkWithRange:(NSRange)range url:(GURL)url {
   DCHECK(url.is_valid());
   if (!_layoutsForURLs)
     _layoutsForURLs.reset([[NSMutableDictionary alloc] init]);
   NSURL* key = net::NSURLWithGURL(url);
   base::scoped_nsobject<LinkLayout> layout(
       [[LinkLayout alloc] initWithRange:range]);
@@ skipping 206 matching lines @@
       if (CGRectContainsPoint(frame, point)) {
         _action.get()(net::GURLWithNSURL(key));
         *stop = YES;
         break;
       }
     }
   }];
 }
 
 @end