Make OAuth2TokenService and subclasses take delegate by unique_ptr

ios/chrome/browser/signin/fake_oauth2_token_service_builder.mm

Index: ios/chrome/browser/signin/fake_oauth2_token_service_builder.mm
diff --git a/ios/chrome/browser/signin/fake_oauth2_token_service_builder.mm b/ios/chrome/browser/signin/fake_oauth2_token_service_builder.mm
index 1afa2d622418e2e4daf253a7cbbfa84c34dd82a4..5d5b0e300f1107c837a477ec19c3b4216679d0b5 100644
--- a/ios/chrome/browser/signin/fake_oauth2_token_service_builder.mm
+++ b/ios/chrome/browser/signin/fake_oauth2_token_service_builder.mm
@@ -17,11 +17,11 @@ std::unique_ptr<KeyedService> BuildFakeOAuth2TokenService(
     web::BrowserState* context) {
   ios::ChromeBrowserState* browser_state =
       ios::ChromeBrowserState::FromBrowserState(context);
-  OAuth2TokenServiceDelegate* delegate =
-      new ProfileOAuth2TokenServiceIOSDelegate(
+  std::unique_ptr<OAuth2TokenServiceDelegate> delegate =
+      base::MakeUnique<ProfileOAuth2TokenServiceIOSDelegate>(
           SigninClientFactory::GetForBrowserState(browser_state),
           base::MakeUnique<ProfileOAuth2TokenServiceIOSProviderImpl>(),
           ios::AccountTrackerServiceFactory::GetForBrowserState(browser_state),
           ios::SigninErrorControllerFactory::GetForBrowserState(browser_state));
-  return base::MakeUnique<FakeProfileOAuth2TokenService>(delegate);
+  return base::MakeUnique<FakeProfileOAuth2TokenService>(std::move(delegate));
 }