MP4 Sometime don't see the END event

[brianchu]

Condition:
Add this mp4 video (it's DFP pre-roll ad demo video) playing in Exoplayer demo:

 public static final Sample[] MISC = new Sample[] {
          new Sample("TEST", "https://r10---sn-o097znls.gvt1.com/videoplayback/id/5bad011a1282b323/itag/15/source/gfp_video_ads/requiressl/yes/ip/76.102.15.70/ipbits/0/expire/1438993673/sparams/expire,id,ip,ipbits,itag,mm,mn,ms,mv,pl,requiressl,source/signature/17BEC66D2612A1C282055B0C3A7FA3B80EA2A655.1ADF81468C2923CE617EBB0A5D87467E65910F89/key/cms1/cms_redirect/yes/mm/29/mn/sn-o097znls/ms/tph/mt/1438972025/mv/m/pl/16/file/file.mp4",
                  DemoUtil.TYPE_MP4),
...

Observation:
Let it play all to the end, it works, saw playbackState from ready to 'ended'.
However, when you drag the control almost to the end (~ 1second before the end), it got stucked in the state:

playWhenReady=true, playbackState=ready

and never proceed to the very end of the video.

The other way to reproduce is the click the Pause button (~ 1 second before the end), same result.

Device:
Samsung S4, S5, HTC M8.

[brianchu]

possible related to issue #596