Add locking around waiting for initialization to finish, since calling dispatch_block_wait from multiple threads leads to undefined behavior. Initialize RTCUIApplicationStatusObserver earlier to give the initialization block more time to run on the main thread before starting to query the application state. http://www.dailymotion.com/video/x2mckmh BUG=b/65558688 Review-Url: https://codereview.webrtc.org/3009383002 Cr-Commit-Position: refs/heads/master@{#19822}