commit 884c336c345d988974c2a69cea402b0fb8b07a63
author Tommi <tommi@webrtc.org> Mon Jun 20 19:42:44 2016 +0200
committer Tommi <tommi@webrtc.org> Mon Jun 20 17:43:10 2016 +0000
tree 8e06a2e86e629bb1531e1e954c4c122b13720bc4
parent 7ebbf9007706ba51be44e065a7c14f18a6d2b009

Reland of IncomingVideoStream refactoring.
This reland does not contain the non-smoothing part of the original implementation.  Instead, when smoothing is turned off, frame callbacks run on the decoder thread, as they did before.  This code path is used in Chrome.  As far as Chrome goes, the difference now is that there won't be an instance of IncomingVideoStream in between the decoder and the callback (i.e. fewer locks).  Other than that, no change for Chrome.

Original issue's description (with non-smoothing references removed):

Split IncomingVideoStream into two implementations, with smoothing and without.

* Added TODOs and documentation for VideoReceiveStream::OnFrame, where we today grab 6 locks.

* Removed the Start/Stop methods from the IncomingVideoStream implementations.  Now, when an instance is created, it should be considered to be "running" and when it is deleted, it's "not running".  This saves on resources and also reduces the amount of locking required and I could remove one critical section altogether.

* Changed the VideoStreamDecoder class to not depend on IncomingVideoStream but rather use the generic rtc::VideoSinkInterface<VideoFrame> interface.  This means that any implementation of that interface can be used and the decoder can be made to  just use the 'renderer' from the config.  Once we do that, we can decouple the IncomingVideoStream implementations from the decoder and VideoReceiveStream implementations and leave it up to the application for how to do smoothing.  The app can choose to use the Incoming* classes or roll its own (which may be preferable since applications often have their own scheduling mechanisms).

* The lifetime of the VideoStreamDecoder instance is now bound to Start/Stop in VideoReceiveStream and not all of the lifetime of VideoReceiveStream.

* Fixed VideoStreamDecoder to unregister callbacks in the dtor that were registered in the ctor. (this was open to a use-after-free regression)

* Delay and callback pointers are now passed via the ctors to the IncomingVideoStream classes.  The thread primitives in the IncomingVideoStream classes are also constructed/destructed at the same time as the owning object, which allowed me to remove one more lock.

* Removed code in the VideoStreamDecoder that could overwrite the VideoReceiveStream render delay with a fixed value of 10ms on construction.  This wasn't a problem with the previous implementation (it would be now though) but seemed to me like the wrong place to be setting that value.

* Made the render delay value in VideoRenderFrames, const.

BUG=chromium:620232
R=mflodman@webrtc.org, nisse@webrtc.org

Review URL: https://codereview.webrtc.org/2078873002 .

Cr-Commit-Position: refs/heads/master@{#13219}