[GCM] Fixing a bug with old registration ID not being removed

google_apis/gcm/engine/gcm_store_impl.cc

Index: google_apis/gcm/engine/gcm_store_impl.cc
diff --git a/google_apis/gcm/engine/gcm_store_impl.cc b/google_apis/gcm/engine/gcm_store_impl.cc
index 3088ab31db363c94a96c9d895b67ef38a09d55f7..f1f46ee3563320dbd3c21c14377de7ba9d20eca6 100644
--- a/google_apis/gcm/engine/gcm_store_impl.cc
+++ b/google_apis/gcm/engine/gcm_store_impl.cc
@@ -358,7 +358,8 @@ void GCMStoreImpl::Backend::RemoveRegistration(const std::string& app_id,
   leveldb::WriteOptions write_options;
   write_options.sync = true;
 
-  leveldb::Status status = db_->Delete(write_options, MakeSlice(app_id));
+  leveldb::Status status =
+      db_->Delete(write_options, MakeSlice(MakeRegistrationKey(app_id)));
   if (status.ok()) {
     foreground_task_runner_->PostTask(FROM_HERE, base::Bind(callback, true));
     return;