Summary:
Sometimes you want to get the sonar client without necessarily wanting to initialize it, for example if you don't have a context object, but still want to get hold of a particular plugin object.
Adds a getInstance method that returns null if not initialized.
Reviewed By: passy
Differential Revision: D9154423
fbshipit-source-id: 65cb46684bc35d9a953dbd958c7cf72aba0015e2
a92b6eaf80