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

ios/chrome/browser/ui/authentication/signin_interaction_controller.mm

Index: ios/chrome/browser/ui/authentication/signin_interaction_controller.mm
diff --git a/ios/chrome/browser/ui/authentication/signin_interaction_controller.mm b/ios/chrome/browser/ui/authentication/signin_interaction_controller.mm
index 1f693f817abf71fb9e411a7811ed9a8ef4add697..c1fc64dcd3f2538f4f30b1e36d724e5d30de31ef 100644
--- a/ios/chrome/browser/ui/authentication/signin_interaction_controller.mm
+++ b/ios/chrome/browser/ui/authentication/signin_interaction_controller.mm
@@ -4,7 +4,6 @@
 
 #import "ios/chrome/browser/ui/authentication/signin_interaction_controller.h"
 
-#include "base/ios/weak_nsobject.h"
 #include "base/logging.h"
 #include "base/mac/scoped_block.h"
 #include "base/mac/scoped_nsobject.h"
@@ -27,6 +26,10 @@
 #import "ios/public/provider/chrome/browser/signin/chrome_identity_interaction_manager.h"
 #import "ios/public/provider/chrome/browser/signin/chrome_identity_service.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 using signin_ui::CompletionCallback;
 
 @interface SigninInteractionController ()<
@@ -35,17 +38,16 @@ using signin_ui::CompletionCallback;
   ios::ChromeBrowserState* browserState_;
   signin_metrics::AccessPoint accessPoint_;
   signin_metrics::PromoAction promoAction_;
-  base::scoped_nsobject<UIViewController> presentingViewController_;
+  UIViewController* presentingViewController_;
   BOOL isPresentedOnSettings_;
   BOOL isCancelling_;
   BOOL isDismissing_;
   BOOL interactionManagerDismissalIgnored_;
-  base::scoped_nsobject<AlertCoordinator> alertCoordinator_;
-  base::mac::ScopedBlock<CompletionCallback> completionCallback_;
-  base::scoped_nsobject<ChromeSigninViewController> signinViewController_;
-  base::scoped_nsobject<ChromeIdentityInteractionManager>
-      identityInteractionManager_;
-  base::scoped_nsobject<ChromeIdentity> signInIdentity_;
+  AlertCoordinator* alertCoordinator_;
+  CompletionCallback completionCallback_;
+  ChromeSigninViewController* signinViewController_;
+  ChromeIdentityInteractionManager* identityInteractionManager_;
+  ChromeIdentity* signInIdentity_;
   BOOL identityAdded_;
 }
 @end
@@ -67,7 +69,7 @@ using signin_ui::CompletionCallback;
     DCHECK(browserState);
     DCHECK(presentingViewController);
     browserState_ = browserState;
-    presentingViewController_.reset([presentingViewController retain]);
+    presentingViewController_ = presentingViewController;
     isPresentedOnSettings_ = isPresentedOnSettings;
     accessPoint_ = accessPoint;
     promoAction_ = promoAction;
@@ -79,7 +81,7 @@ using signin_ui::CompletionCallback;
   // Cancelling and dismissing the |identityInteractionManager_| may call the
   // |completionCallback_| which could lead to |self| being released before the
   // end of this method. |self| is retained here to prevent this from happening.
-  base::scoped_nsobject<SigninInteractionController> strongSelf([self retain]);
+  base::scoped_nsobject<SigninInteractionController> strongSelf(self);

[msarda, 2017/06/12 12:49:13]

Is this correct? I t there should not be any usage of scoped_nsobject left after
migrating to ARC.

[marq (ping after 24h), 2017/06/12 14:20:40]

I had kept it there because I didn't know what the behavior of an unused strong
pointer under ARC would be, but I guess (after thinking about it) that it would
work fine. It looks like some other classes do the same thing.

   isCancelling_ = YES;
   [alertCoordinator_ executeCancelHandler];
   [alertCoordinator_ stop];
@@ -98,7 +100,7 @@ using signin_ui::CompletionCallback;
                         identity:(ChromeIdentity*)identity
                       completion:(signin_ui::CompletionCallback)completion {
   signin_metrics::LogSigninAccessPointStarted(accessPoint_, promoAction_);
-  completionCallback_.reset(completion, base::scoped_policy::RETAIN);
+  completionCallback_ = completion;

[msarda, 2017/06/12 12:49:13]

Here and everywhere else we use ScopedBlock with RETAIN policy:

I think the retain policy actually lead to a copy of the block - see
https://cs.chromium.org/chromium/src/base/mac/scoped_block.h?rcl=feb596f1bd91...
.

I think this will no longer be the case (the block will just be retained, not
copied). 

[marq (ping after 24h), 2017/06/12 14:20:40]

Changed all simple assignments to [foo copy].

   ios::ChromeIdentityService* identityService =
       ios::GetChromeBrowserProvider()->GetChromeIdentityService();
   if (identity) {
@@ -119,7 +121,7 @@ using signin_ui::CompletionCallback;
       return;
     }
 
-    base::WeakNSObject<SigninInteractionController> weakSelf(self);
+    __weak SigninInteractionController* weakSelf = self;
     [identityInteractionManager_
         addAccountWithCompletion:^(ChromeIdentity* identity, NSError* error) {
           [weakSelf handleIdentityAdded:identity
@@ -133,7 +135,7 @@ using signin_ui::CompletionCallback;
 - (void)reAuthenticateWithCompletion:(CompletionCallback)completion
                       viewController:(UIViewController*)viewController {
   signin_metrics::LogSigninAccessPointStarted(accessPoint_, promoAction_);
-  completionCallback_.reset(completion, base::scoped_policy::RETAIN);
+  completionCallback_ = completion;
   AccountInfo accountInfo =
       ios::SigninManagerFactory::GetForBrowserState(browserState_)
           ->GetAuthenticatedAccountInfo();
@@ -158,7 +160,7 @@ using signin_ui::CompletionCallback;
       ios::GetChromeBrowserProvider()
           ->GetChromeIdentityService()
           ->NewChromeIdentityInteractionManager(browserState_, self);
-  base::WeakNSObject<SigninInteractionController> weakSelf(self);
+  __weak SigninInteractionController* weakSelf = self;
   [identityInteractionManager_
       reauthenticateUserWithID:base::SysUTF8ToNSString(idToReauthenticate)
                          email:base::SysUTF8ToNSString(emailToReauthenticate)
@@ -172,12 +174,12 @@ using signin_ui::CompletionCallback;
 
 - (void)addAccountWithCompletion:(CompletionCallback)completion
                   viewController:(UIViewController*)viewController {
-  completionCallback_.reset(completion, base::scoped_policy::RETAIN);
+  completionCallback_ = completion;
   identityInteractionManager_ =
       ios::GetChromeBrowserProvider()
           ->GetChromeIdentityService()
           ->NewChromeIdentityInteractionManager(browserState_, self);
-  base::WeakNSObject<SigninInteractionController> weakSelf(self);
+  __weak SigninInteractionController* weakSelf = self;
   [identityInteractionManager_
       addAccountWithCompletion:^(ChromeIdentity* identity, NSError* error) {
         [weakSelf handleIdentityAdded:identity
@@ -203,15 +205,14 @@ using signin_ui::CompletionCallback;
       return;
     }
 
-    base::WeakNSObject<SigninInteractionController> weakSelf(self);
+    __weak SigninInteractionController* weakSelf = self;
     ProceduralBlock dismissAction = ^{
       [weakSelf runCompletionCallbackWithSuccess:NO executeCommand:nil];
     };
 
-    alertCoordinator_.reset([ios_internal::ErrorCoordinator(
+    alertCoordinator_ = ios_internal::ErrorCoordinator(
         error, dismissAction,
-        top_view_controller::TopPresentedViewControllerFrom(viewController))
-        retain]);
+        top_view_controller::TopPresentedViewControllerFrom(viewController));
     [alertCoordinator_ start];
     return;
   }
@@ -266,18 +267,18 @@ using signin_ui::CompletionCallback;
 
 - (void)showSigninViewControllerWithIdentity:(ChromeIdentity*)signInIdentity
                                identityAdded:(BOOL)identityAdded {
-  signinViewController_.reset([[ChromeSigninViewController alloc]
+  signinViewController_ = [[ChromeSigninViewController alloc]
        initWithBrowserState:browserState_
       isPresentedOnSettings:isPresentedOnSettings_
                 accessPoint:accessPoint_
                 promoAction:promoAction_
-             signInIdentity:signInIdentity]);
+             signInIdentity:signInIdentity];
   [signinViewController_ setDelegate:self];
   [signinViewController_
       setModalPresentationStyle:UIModalPresentationFormSheet];
   [signinViewController_
       setModalTransitionStyle:UIModalTransitionStyleCoverVertical];
-  signInIdentity_.reset([signInIdentity retain]);
+  signInIdentity_ = signInIdentity;
   identityAdded_ = identityAdded;
 
   UIViewController* presentingViewController = presentingViewController_;
@@ -315,27 +316,27 @@ using signin_ui::CompletionCallback;
 #pragma mark - ChromeSigninViewControllerDelegate
 
 - (void)willStartSignIn:(ChromeSigninViewController*)controller {
-  DCHECK_EQ(controller, signinViewController_.get());
+  DCHECK_EQ(controller, signinViewController_);
 }
 
 - (void)willStartAddAccount:(ChromeSigninViewController*)controller {
-  DCHECK_EQ(controller, signinViewController_.get());
+  DCHECK_EQ(controller, signinViewController_);
 }
 
 - (void)didSkipSignIn:(ChromeSigninViewController*)controller {
-  DCHECK_EQ(controller, signinViewController_.get());
+  DCHECK_EQ(controller, signinViewController_);
   [self dismissSigninViewControllerWithSignInSuccess:NO executeCommand:nil];
 }
 
 - (void)didSignIn:(ChromeSigninViewController*)controller {
-  DCHECK_EQ(controller, signinViewController_.get());
+  DCHECK_EQ(controller, signinViewController_);
 }
 
 - (void)didUndoSignIn:(ChromeSigninViewController*)controller
              identity:(ChromeIdentity*)identity {
-  DCHECK_EQ(controller, signinViewController_.get());
-  if ([signInIdentity_.get() isEqual:identity]) {
-    signInIdentity_.reset();
+  DCHECK_EQ(controller, signinViewController_);
+  if ([signInIdentity_ isEqual:identity]) {
+    signInIdentity_ = nil;
     if (identityAdded_) {
       // This is best effort. If the operation fails, the account will be left
       // on the device. The user will not be warned either as this call is
@@ -350,13 +351,13 @@ using signin_ui::CompletionCallback;
 }
 
 - (void)didFailSignIn:(ChromeSigninViewController*)controller {
-  DCHECK_EQ(controller, signinViewController_.get());
+  DCHECK_EQ(controller, signinViewController_);
   [self dismissSigninViewControllerWithSignInSuccess:NO executeCommand:nil];
 }
 
 - (void)didAcceptSignIn:(ChromeSigninViewController*)controller
          executeCommand:(GenericChromeCommand*)command {
-  DCHECK_EQ(controller, signinViewController_.get());
+  DCHECK_EQ(controller, signinViewController_);
   [self dismissSigninViewControllerWithSignInSuccess:YES
                                       executeCommand:command];
 }
@@ -373,16 +374,16 @@ using signin_ui::CompletionCallback;
     [self dismissPresentedViewControllersAnimated:YES completion:nil];
   }
 
-  identityInteractionManager_.reset();
-  signinViewController_.reset();
+  identityInteractionManager_ = nil;
+  signinViewController_ = nil;
   UIViewController* presentingViewController = presentingViewController_;
   // Ensure self is not destroyed in the callbacks.
-  base::scoped_nsobject<SigninInteractionController> strongSelf([self retain]);
+  SigninInteractionController* strongSelf = self;
   if (completionCallback_) {
-    completionCallback_.get()(success);
-    completionCallback_.reset();
+    completionCallback_(success);
+    completionCallback_ = nil;
   }
-  strongSelf.reset();
+  strongSelf = nil;
   if (command) {
     [presentingViewController chromeExecuteCommand:command];
   }