Reduce usage of FOR_EACH_OBSERVER macro in components/

components/proximity_auth/cryptauth/mock_cryptauth_client.cc

Index: components/proximity_auth/cryptauth/mock_cryptauth_client.cc
diff --git a/components/proximity_auth/cryptauth/mock_cryptauth_client.cc b/components/proximity_auth/cryptauth/mock_cryptauth_client.cc
index 51dd4eb8201aaae8a7eb39ef33388b890683d263..4480623e7d01dfed541eae82ff662c705edb76d0 100644
--- a/components/proximity_auth/cryptauth/mock_cryptauth_client.cc
+++ b/components/proximity_auth/cryptauth/mock_cryptauth_client.cc
@@ -30,8 +30,8 @@ std::unique_ptr<CryptAuthClient> MockCryptAuthClientFactory::CreateInstance() {
   else
     client.reset(new testing::NiceMock<MockCryptAuthClient>());
 
-  FOR_EACH_OBSERVER(Observer, observer_list_,
-                    OnCryptAuthClientCreated(client.get()));
+  for (auto& observer : observer_list_)
+    observer.OnCryptAuthClientCreated(client.get());
   return std::move(client);
 }