Introduce audio/video BufferingState to Pipeline.

Introduce audio/video BufferingState to Pipeline.

This is a stepping stone towards having audio/video renderers accurately
report their buffering state. For now we use the Preroll() callback to
signal that enough data has been buffered.

Notable changes:
  - The kStarting/kStarted states have been merged into kPlaying
  - DoPlay() is now done implicitly after entering the kPlaying state
  - Transitioning from waiting to non-waiting states (or vice versa)
    now controls the starting and stopping of playback

BUG=144683
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=269828

[acolwell GONE FROM CHROMIUM, 2014-05-12 13:46:54]

lgtm

https://codereview.chromium.org/276973004/diff/40001/media/base/pipeline.cc
File media/base/pipeline.cc (right):

https://codereview.chromium.org/276973004/diff/40001/media/base/pipeline.cc#n...
media/base/pipeline.cc:895: void
Pipeline::AudioBufferingStateChanged(BufferingState buffering_state) {
nit: You could avoid duplicate code below if you bound the xxx_buffering_state_
to the callback so it could be passed in as a parameter here.

https://codereview.chromium.org/276973004/diff/40001/media/base/pipeline.cc#n...
media/base/pipeline.cc:961: // We use video stream to update the clock. So if
there is such a
nit: s/video/audio?

[scherkus (not reviewing), 2014-05-12 15:21:41]

The CQ bit was checked by scherkus@chromium.org

[scherkus (not reviewing), 2014-05-12 15:22:03]

https://codereview.chromium.org/276973004/diff/40001/media/base/pipeline.cc
File media/base/pipeline.cc (right):

https://codereview.chromium.org/276973004/diff/40001/media/base/pipeline.cc#n...
media/base/pipeline.cc:895: void
Pipeline::AudioBufferingStateChanged(BufferingState buffering_state) {
On 2014/05/12 13:46:54, acolwell_OOO_5-12_to_5-15 wrote:
> nit: You could avoid duplicate code below if you bound the
xxx_buffering_state_
> to the callback so it could be passed in as a parameter here.

Done.

https://codereview.chromium.org/276973004/diff/40001/media/base/pipeline.cc#n...
media/base/pipeline.cc:961: // We use video stream to update the clock. So if
there is such a
On 2014/05/12 13:46:54, acolwell_OOO_5-12_to_5-15 wrote:
> nit: s/video/audio?

Done.

[commit-bot: I haz the power, 2014-05-12 15:22:07]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/scherkus@chromium.org/276973004/60001

[commit-bot: I haz the power, 2014-05-12 18:48:41]

Change committed as 269828