[ObjC ARC] Converts components/signin/ios/browser:browser to ARC.

components/signin/ios/browser/account_consistency_service.mm

Index: components/signin/ios/browser/account_consistency_service.mm
diff --git a/components/signin/ios/browser/account_consistency_service.mm b/components/signin/ios/browser/account_consistency_service.mm
index 5f15df39e15e2604550f824dfd693f65c3ab9d2e..f1ec5c76734a05c86275387a658888fd284ed277 100644
--- a/components/signin/ios/browser/account_consistency_service.mm
+++ b/components/signin/ios/browser/account_consistency_service.mm
@@ -6,7 +6,6 @@
 
 #import <WebKit/WebKit.h>
 
-#import "base/ios/weak_nsobject.h"
 #include "base/logging.h"
 #import "base/mac/foundation_util.h"
 #include "base/macros.h"
@@ -24,6 +23,10 @@
 #include "net/base/registry_controlled_domains/registry_controlled_domain.h"
 #include "url/gurl.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace {
 
 // Threshold (in hours) used to control whether the CHROME_CONNECTED cookie
@@ -58,7 +61,7 @@ class AccountConsistencyHandler : public web::WebStatePolicyDecider {
 
   AccountConsistencyService* account_consistency_service_;  // Weak.
   AccountReconcilor* account_reconcilor_;                   // Weak.
-  base::WeakNSProtocol<id<ManageAccountsDelegate>> delegate_;
+  __weak id<ManageAccountsDelegate> delegate_;
 };
 }
 
@@ -390,11 +393,11 @@ WKWebView* AccountConsistencyService::GetWKWebView() {
     return nil;
   }
   if (!web_view_) {
-    web_view_.reset([BuildWKWebView() retain]);
-    navigation_delegate_.reset([[AccountConsistencyNavigationDelegate alloc]
+    web_view_.reset(BuildWKWebView());

[msarda, 2017/06/13 13:15:30]

I think this will assign an object that is autoreleased to a scoped_nsobject.

This code is very tricky - may I ask you to do the following test:
* Fresh install Chrome.
* Start Chrome and from settings sign in to Chrome with any Google account.
* Go to mail.google.com and observe if you are signed in to gmail.

[marq (ping after 24h), 2017/06/15 09:27:33]

It should have (had I kept it a scoped object), under ARC, seen that the scoped
object keeps a strong reference. But it's just a simple assignment now.
 
That work fine, thanks for the test steps!

+    navigation_delegate_ = [[AccountConsistencyNavigationDelegate alloc]
         initWithCallback:base::Bind(&AccountConsistencyService::
                                         FinishedApplyingCookieRequest,
-                                    base::Unretained(this), true)]);
+                                    base::Unretained(this), true)];
     [web_view_ setNavigationDelegate:navigation_delegate_];
   }
   return web_view_.get();
@@ -408,7 +411,7 @@ void AccountConsistencyService::ResetWKWebView() {
   [web_view_ setNavigationDelegate:nil];
   [web_view_ stopLoading];
   web_view_.reset();
-  navigation_delegate_.reset();
+  navigation_delegate_ = nil;
   applying_cookie_requests_ = false;
 }