Changes:
1. Removed _voiceEngineObserver boolean flag, because its value is equal to (_voiceEngineObserverPtr != NULL).
2. Removed WEBRTC_TRACE macro usage wherever it was unnecessary to log. Replaced its usage with LOG_F (new and preferred way to log messages) wherever it is useful to log.
3. Replaced asserts with CHECKs.
Discussion:
To make it easier to review the changes, I didn't reformat the code to make it compliant to the new coding standards. It is up for debate how much reformatting to do: the whole file/class or just the methods that I have touched. My vote - go for the whole class.
R=henrika@webrtc.org, kwiberg@webrtc.org
Review URL: https://webrtc-codereview.appspot.com/51579004
Cr-Commit-Position: refs/heads/master@{#8983}
9e5e421b7d