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

ios/chrome/browser/tabs/tab.h

Index: ios/chrome/browser/tabs/tab.h
diff --git a/ios/chrome/browser/tabs/tab.h b/ios/chrome/browser/tabs/tab.h
index 43091fc27ee1f0c3d3c327650d3af6d9afa5864d..075f848a416eda07391701c432525a96aa644fe6 100644
--- a/ios/chrome/browser/tabs/tab.h
+++ b/ios/chrome/browser/tabs/tab.h
@@ -113,7 +113,7 @@ extern NSString* const kProxyPassthroughHeaderValue;
 @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;
@@ -133,27 +133,27 @@ extern NSString* const kProxyPassthroughHeaderValue;
 @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;