[ios] ARCMigrate ios/chrome/browser/tabs/tab.mm to ARC.

ios/chrome/browser/tabs/tab.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_TABS_TAB_H_
 #define IOS_CHROME_BROWSER_TABS_TAB_H_
 
 #import <UIKit/UIKit.h>
 
 #include <memory>
@@ skipping 95 matching lines @@
 // Do not add new calls to this method.
 @property(nonatomic, readonly) const GURL& url;
 
 // Returns the URL of the last committed NavigationItem for this Tab.
 @property(nonatomic, readonly) const GURL& lastCommittedURL;
 
 // Returns the URL of the visible NavigationItem for this Tab.
 @property(nonatomic, readonly) const GURL& visibleURL;
 
 // The Passkit Dialog provider used to show the UI to download a passkit object.
-@property(nonatomic, assign) id<PassKitDialogProvider> passKitDialogProvider;
+@property(nonatomic, weak) id<PassKitDialogProvider> passKitDialogProvider;
 
 // The current title of the tab.
 @property(nonatomic, readonly) NSString* title;
 
 // Original page title or nil if the page did not provide one.
 @property(nonatomic, readonly) NSString* originalTitle;
 
 @property(nonatomic, readonly) NSString* urlDisplayString;
 
 // ID associated with this tab.
 @property(nonatomic, readonly) NSString* tabId;
 
 // |YES| if snapshot overlay should load from the grey image cache.
 @property(nonatomic, assign) BOOL useGreyImageCache;
 
 // The Webstate associated with this Tab.
 @property(nonatomic, readonly) web::WebState* webState;
 
 @property(nonatomic, readonly) CRWWebController* webController;
+
+// Handles saving and autofill of passwords.
 @property(nonatomic, readonly) PasswordController* passwordController;
 @property(nonatomic, readonly) BOOL canGoBack;
 @property(nonatomic, readonly) BOOL canGoForward;
-@property(nonatomic, assign) id<TabDelegate> delegate;
-@property(nonatomic, assign) id<TabHeadersDelegate> tabHeadersDelegate;
-@property(nonatomic, assign) id<TabSnapshottingDelegate>
-    tabSnapshottingDelegate;
+@property(nonatomic, weak) id<TabDelegate> delegate;
+@property(nonatomic, weak) id<TabHeadersDelegate> tabHeadersDelegate;
+@property(nonatomic, weak) id<TabSnapshottingDelegate> tabSnapshottingDelegate;
 @property(nonatomic, readonly) id<FindInPageControllerDelegate>
     findInPageControllerDelegate;
 
 // Whether or not desktop user agent is used for the currently visible page.
 @property(nonatomic, readonly) BOOL usesDesktopUserAgent;
 
-@property(nonatomic, assign) id<FullScreenControllerDelegate>
+@property(nonatomic, weak) id<FullScreenControllerDelegate>
     fullScreenControllerDelegate;
 @property(nonatomic, readonly)
     OverscrollActionsController* overscrollActionsController;
-@property(nonatomic, assign) id<OverscrollActionsControllerDelegate>
+@property(nonatomic, weak) id<OverscrollActionsControllerDelegate>
     overscrollActionsControllerDelegate;
-@property(nonatomic, assign) id<SnapshotOverlayProvider>
-    snapshotOverlayProvider;
+@property(nonatomic, weak) id<SnapshotOverlayProvider> snapshotOverlayProvider;
 
 // Delegate used to show HTTP Authentication dialogs.
 @property(nonatomic, weak) id<TabDialogDelegate> dialogDelegate;
 
 // TODO(crbug.com/661663): Should this property abstract away the concept of
 // prerendering?  Maybe this can move to the TabDelegate interface.
 @property(nonatomic, assign) BOOL isPrerenderTab;
 @property(nonatomic, assign) BOOL isLinkLoadingPrerenderTab;
 @property(nonatomic, assign) BOOL isVoiceSearchResultsTab;
 
@@ skipping 134 matching lines @@
 // Evaluates U2F result.
 - (void)evaluateU2FResultFromURL:(const GURL&)url;
 
 // Cancels prerendering. It is an error to call this on anything except a
 // prerender tab (where |isPrerenderTab| is set to YES).
 - (void)discardPrerender;
 
 @end
 
 #endif  // IOS_CHROME_BROWSER_TABS_TAB_H_