Reland of Collecting encode_time_ms for each frame

Reland of Collecting encode_time_ms for each frame (patchset #1 id:1 of https://codereview.webrtc.org/1383283005/ )

Reason for revert:
The reverted commit didn't affect the tests, but the one before: https://codereview.webrtc.org/1385563005/

I've run the test that was failing (EndToEndTest.AssignsTransportSequenceNumbers) locally multiple times, and it works fine (finishes successfully in 150-170ms).

Original issue's description:
> Revert of Collecting encode_time_ms for each frame (patchset #13 id:220001 of https://codereview.webrtc.org/1374233002/ )
>
> Reason for revert:
> Breaks EndToEndTest.AssignsTransportSequenceNumbers in video_engine_tests
> on several bots:
> http://build.chromium.org/p/client.webrtc/builders/Linux64%20Debug/builds/5507
> http://build.chromium.org/p/client.webrtc/builders/Mac64%20Debug/builds/4815
> http://build.chromium.org/p/client.webrtc/builders/Win%20SyzyASan/builds/3272
> http://build.chromium.org/p/client.webrtc/builders/Linux%20Memcheck/builds/4414
>
> It seems very unfortunate that it breaks on _exactly_ the bot configs that aren't covered by the CQ trybots.
>
> Original issue's description:
> > Collecting encode_time_ms for each frame.
> >
> > Also, in Sample struct, replacing double with the original type.
> > It makes more sense to save the original data as truthful as possible, and then
> > convert it to double later if necessary (in the plot script).
> >
> > Committed: https://crrev.com/092b13384e57b33e2003d9736dfa1f491e76f938
> > Cr-Commit-Position: refs/heads/master@{#10184}
>
> TBR=sprang@webrtc.org,pbos@webrtc.org,mflodman@webrtc.org,asapersson@webrtc.org,ivica@webrtc.org
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
>
> Committed: https://crrev.com/810447972425e890bc7911af27f894b86e9b7e6f
> Cr-Commit-Position: refs/heads/master@{#10185}

TBR=sprang@webrtc.org,pbos@webrtc.org,mflodman@webrtc.org,asapersson@webrtc.org,kjellander@webrtc.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Committed: https://crrev.com/8d15bd6dabae829d27443e17f2f02cfbe6fa6525
Cr-Commit-Position: refs/heads/master@{#10195}

[ivica, 2015-10-07 09:42:52]

Created Reland of Collecting encode_time_ms for each frame

[commit-bot: I haz the power, 2015-10-07 09:43:08]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1390163002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1390163002/1

[commit-bot: I haz the power, 2015-10-07 09:43:17]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-10-07 09:43:35]

Patchset 1 (id:??) landed as
https://crrev.com/8d15bd6dabae829d27443e17f2f02cfbe6fa6525
Cr-Commit-Position: refs/heads/master@{#10195}

[kjellander_webrtc, 2015-10-07 11:20:03]

lgtm

[mflodman, 2015-10-07 11:25:14]

LGTM