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

ios/chrome/browser/signin/chrome_identity_service_observer_bridge_unittest.mm

Index: ios/chrome/browser/signin/chrome_identity_service_observer_bridge_unittest.mm
diff --git a/ios/chrome/browser/signin/chrome_identity_service_observer_bridge_unittest.mm b/ios/chrome/browser/signin/chrome_identity_service_observer_bridge_unittest.mm
index fa0eff59debf22f8ec8e9fdc1611a079d0b830e9..ae034c27e094a74d9f9441a5d0167154e7d18965 100644
--- a/ios/chrome/browser/signin/chrome_identity_service_observer_bridge_unittest.mm
+++ b/ios/chrome/browser/signin/chrome_identity_service_observer_bridge_unittest.mm
@@ -6,20 +6,23 @@
 
 #include <memory>
 
-#include "base/mac/scoped_nsobject.h"
 #import "ios/public/provider/chrome/browser/signin/chrome_identity.h"
 #include "ios/public/provider/chrome/browser/signin/chrome_identity_service.h"
 #include "testing/gtest_mac.h"
 #include "testing/platform_test.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 @interface TestChromeIdentityServiceObserver
     : NSObject<ChromeIdentityServiceObserver>
 @property(nonatomic) BOOL onIdentityListChangedCalled;
 @property(nonatomic) BOOL onAccessTokenRefreshFailedCalled;
 @property(nonatomic) BOOL onProfileUpdateCalled;
 @property(nonatomic) BOOL onChromeIdentityServiceWillBeDestroyedCalled;
-@property(nonatomic, assign) ChromeIdentity* identity;
-@property(nonatomic, readonly) NSDictionary* userInfo;
+@property(nonatomic, weak) ChromeIdentity* identity;
+@property(weak, nonatomic, readonly) NSDictionary* userInfo;
 @property(nonatomic, readonly)
     ios::ChromeIdentityService::Observer* observerBridge;
 @end
@@ -88,7 +91,7 @@ class ChromeIdentityServiceObserverBridgeTest : public PlatformTest {
   }
 
  private:
-  base::scoped_nsobject<TestChromeIdentityServiceObserver> test_observer_;
+  TestChromeIdentityServiceObserver* test_observer_;
 };
 
 // Tests that |onIdentityListChanged| is forwarded.
@@ -103,7 +106,7 @@ TEST_F(ChromeIdentityServiceObserverBridgeTest, onIdentityListChanged) {
 
 // Tests that |onAccessTokenRefreshFailed| is forwarded.
 TEST_F(ChromeIdentityServiceObserverBridgeTest, onAccessTokenRefreshFailed) {
-  base::scoped_nsobject<ChromeIdentity> identity([[ChromeIdentity alloc] init]);
+  ChromeIdentity* identity = [[ChromeIdentity alloc] init];
   NSDictionary* userInfo = [NSDictionary dictionary];
   ASSERT_FALSE(GetTestObserver().onAccessTokenRefreshFailedCalled);
   GetObserverBridge()->OnAccessTokenRefreshFailed(identity, userInfo);
@@ -117,7 +120,7 @@ TEST_F(ChromeIdentityServiceObserverBridgeTest, onAccessTokenRefreshFailed) {
 
 // Tests that |onProfileUpdate| is forwarded.
 TEST_F(ChromeIdentityServiceObserverBridgeTest, onProfileUpdate) {
-  base::scoped_nsobject<ChromeIdentity> identity([[ChromeIdentity alloc] init]);
+  ChromeIdentity* identity = [[ChromeIdentity alloc] init];
   ASSERT_FALSE(GetTestObserver().onProfileUpdateCalled);
   GetObserverBridge()->OnProfileUpdate(identity);
   EXPECT_FALSE(GetTestObserver().onIdentityListChangedCalled);