Presentation API: startSession() no longer takes a presentation id.

Presentation API: startSession() no longer takes a presentation id.

This is part of a suite of three CLs:
1. https://codereview.chromium.org/1208083004
2. <this>
3. https://codereview.chromium.org/1221093004

BUG=502047
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=198635

[mlamouri (slow - plz ping), 2015-07-02 17:37:05]

mlamouri@chromium.org changed reviewers:
+ avayvod@chromium.org

[whywhat, 2015-07-02 21:56:32]

lgtm

[mark a. foltz, 2015-07-06 20:48:23]

mfoltz@chromium.org changed reviewers:
+ mfoltz@chromium.org

[mark a. foltz, 2015-07-06 20:48:24]

lgtm

[mlamouri (slow - plz ping), 2015-07-08 10:00:49]

The CQ bit was checked by mlamouri@chromium.org

[commit-bot: I haz the power, 2015-07-08 10:01:32]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1225523002/1

[commit-bot: I haz the power, 2015-07-08 10:04:25]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-07-08 10:04:26]

Try jobs failed on following builders:
  mac_blink_compile_dbg on tryserver.blink (JOB_FAILED,
http://build.chromium.org/p/tryserver.blink/builders/mac_blink_compile_dbg/bu...)
  mac_blink_rel on tryserver.blink (JOB_FAILED,
http://build.chromium.org/p/tryserver.blink/builders/mac_blink_rel/builds/62129)

[mlamouri (slow - plz ping), 2015-07-09 20:59:33]

The CQ bit was checked by mlamouri@chromium.org

[mlamouri (slow - plz ping), 2015-07-09 20:59:34]

The patchset sent to the CQ was uploaded after l-g-t-m from mfoltz@chromium.org,
avayvod@chromium.org
Link to the patchset: https://codereview.chromium.org/1225523002/#ps20001
(title: "rebase")

[commit-bot: I haz the power, 2015-07-09 21:00:02]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1225523002/20001

[commit-bot: I haz the power, 2015-07-09 22:29:01]

Committed patchset #2 (id:20001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=198635