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

ios/chrome/browser/ui/stack_view/card_set.h

 // Copyright 2012 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.
 
 #ifndef IOS_CHROME_BROWSER_UI_STACK_VIEW_CARD_SET_H_
 #define IOS_CHROME_BROWSER_UI_STACK_VIEW_CARD_SET_H_
 
 #import <UIKit/UIKit.h>
 #include <vector>
 
@@ skipping 29 matching lines @@
 // be cleared, and any card setup done again for the whole card set.
 // This is also called on initial creation of the card set.
 - (void)cardSetRecreatedCards:(CardSet*)cardSet;
 
 @end
 
 // Manager for constructing a set of StackCards and displaying them in a view.
 @interface CardSet : NSObject
 // The layout manager for the set.
 // TODO(stuartmorgan): See if this can reasonably be internalized.
-@property(nonatomic, readonly) CardStackLayoutManager* stackModel;
+@property(weak, nonatomic, readonly) CardStackLayoutManager* stackModel;

[stkhapugin, 2017/06/16 13:17:50]

It seems like these four properties are all strong / might be replaced with just
methods to avoid confusion. 

[marq (ping after 24h), 2017/06/19 10:34:24]

I'll make them not-weak, but I don't want to fiddle with the API.

 // An array of StackCards in the same order as the tabs in the tab model.
-@property(nonatomic, readonly) NSArray* cards;
+@property(weak, nonatomic, readonly) NSArray* cards;
 // The card corresponding to the currently selected tab in the tab model.
 // Setting this property will change the selection in the tab model.
-@property(nonatomic, assign, readwrite) StackCard* currentCard;
+@property(nonatomic, weak, readwrite) StackCard* currentCard;
 // Set to the card that is currently animating closed, if any.
-@property(nonatomic, assign, readwrite) StackCard* closingCard;
+@property(nonatomic, weak, readwrite) StackCard* closingCard;
 // The view that cards should be displayed in. Changing the display view will
 // remove cards from the previous view, but they will not be re-displayed in the
 // new view without a call to updateCardVisibilities.
-@property(nonatomic, retain, readwrite) UIView* displayView;
+@property(nonatomic, strong, readwrite) UIView* displayView;
 // The side on which the close button should be displayed.
 @property(nonatomic, readonly) CardCloseButtonSide closeButtonSide;
 // The object to be notified about addition and removal of cards.
-@property(nonatomic, assign, readwrite) id<CardSetObserver> observer;
+@property(nonatomic, weak, readwrite) id<CardSetObserver> observer;
 // While YES, changes to the tab model will not affect the card stack. When
 // this is changed back to NO, the card stack will be completely rebuilt, so
 // this should be used very carefully.
 @property(nonatomic, assign, readwrite) BOOL ignoresTabModelChanges;
 // While set to YES, |updateCardVisibilities| will elide setting the views
 // of covered cards to hidden. Setting to NO will trigger a call to
 // |updateCardVisibilities| to hide any covered views. Can be set to YES
 // during animations to ensure that cards being animated to not-visible
 // positions remain visible throughout the animation; should be set back to
 // NO on the completion of such animations. Default value is NO.
@@ skipping 146 matching lines @@
 - (void)updateShadowLayout;
 
 @end
 
 @interface CardSet (Testing)
 - (StackCard*)cardForTab:(Tab*)tab;
 - (void)setStackModelForTesting:(CardStackLayoutManager*)stackModel;
 @end
 
 #endif  // IOS_CHROME_BROWSER_UI_STACK_VIEW_CARD_SET_H_