The bundle class extends ContainerAware so the DI component is a required dependency of the bundle.
@@ -17,6 +17,7 @@
],
"require": {
"php": ">=5.3.2",
+ "symfony/dependency-injection": "self.version",
"symfony/event-dispatcher": "self.version",
"symfony/http-kernel": "self.version",
"symfony/routing": "self.version",