Preview in Camera2 is lagging

[dmitry-zaitsev]

Preview of Camera2 is significantly slower than preview of Camera1 while using the same device (in particular on Moto G3).

I already did some research and asked the question (with a bounty on it) on StackOverflow: http://stackoverflow.com/q/43687624/926907

If we won't get our answer until bounty expires we'll have to drop support of frame processors in Camera2.

[dmitry-zaitsev]

Unfortunately there is still no answer to this question, so we will have to remove frame processing functionality from Camera2 from now (or at least make it disabled by default).

[dmitry-zaitsev]

Removed preview callbacks in Camera2. Added log message with a warning.