cl was originally reviewed here: https://codereview.webrtc.org/2060403002/ - Add task queue to Call with the intent of replacing the use of one of the process threads. - Split VideoSendStream in two. VideoSendStreamInternal is created and used on the new task queue. - BitrateAllocator is now created on libjingle's worker thread but always used on the new task queue instead of both encoder threads and the process thread. - VideoEncoderConfig and VideoSendStream::Config support move semantics. - The encoder thread is moved from VideoSendStream to ViEEncoder. Frames are forwarded directly to ViEEncoder which is responsible for timestamping ? and encoding the frames. TBR=mflodman@webrtc.org BUG=webrtc:5687 Review-Url: https://codereview.webrtc.org/2250123002 Cr-Commit-Position: refs/heads/master@{#14014}