Make sure to synchronize on references to plugin dependencies

    }

    public <T> void allowPluginDependency(Class<T> cls, T obj) {

        synchronized (mDependencies) {

            mDependencies.put(cls, obj);

        }

    }

    @Override

    <T> T get(Plugin p, Class<T> cls) {

        if (!mManager.dependsOn(p, cls)) {

            throw new IllegalArgumentException(p.getClass() + " does not depend on " + cls);

        }

        synchronized (mDependencies) {

            if (!mDependencies.containsKey(cls)) {

                throw new IllegalArgumentException("Unknown dependency " + cls);

            }

            return (T) mDependencies.get(cls);

        }

    }

}