private void injectCacheEntryFactoryWithStreamProvider(org.apache.ambari.server.controller.metrics.ganglia.TestStreamProvider streamProvider) throws Exception {
    Field field = TimelineMetricCacheEntryFactory.class.getDeclaredField("requestHelperForGets");
    field.setAccessible(true);
    field.set(cacheEntryFactory, new MetricsRequestHelper(streamProvider));
  }
Test singleton accessor.  Public since instantiated via reflection.
ambari-server/src/test/java/org/apache/ambari/server/controller/internal/StackDefinedPropertyProviderTest.java