Change the type of session_id() from string to int64_t.

Change the type of session_id() from string to int64_t.

BUG=webrtc:7311
Review-Url: https://codereview.webrtc.org/2749493002
Cr-Commit-Position: refs/heads/master@{#17215}
Committed: https://chromium.googlesource.com/external/webrtc/+/30e0da4a65d4ded14a9158b61548ce09d7cc95c1

[Zhi Huang, 2017-03-13 04:22:08]

The CQ bit was checked by zhihuang@webrtc.org to run a CQ dry run

[commit-bot: I haz the power, 2017-03-13 04:22:19]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.webrtc.org/...

[Zhi Huang, 2017-03-13 04:25:42]

zhihuang@webrtc.org changed reviewers:
+ deadbeef@webrtc.org

[Zhi Huang, 2017-03-13 04:25:43]

Hi Taylor,
This is a follow up CL to address the comments about type of the sessioin id.
Please take a look.
Thanks.

[commit-bot: I haz the power, 2017-03-13 04:40:57]

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

[commit-bot: I haz the power, 2017-03-13 04:40:58]

Dry run: This issue passed the CQ dry run.

[Taylor Brandstetter, 2017-03-13 17:51:40]

lgtm

[Zhi Huang, 2017-03-13 17:58:17]

The CQ bit was checked by zhihuang@webrtc.org

[commit-bot: I haz the power, 2017-03-13 17:58:22]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.webrtc.org/...

[commit-bot: I haz the power, 2017-03-13 18:00:54]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1489427897081710, "parent_rev":
"d92f5ba9a70d82f3cdb15ea332165c52408295a4", "commit_rev":
"30e0da4a65d4ded14a9158b61548ce09d7cc95c1"}

[commit-bot: I haz the power, 2017-03-13 18:00:57]

Description was changed from

==========
Change the type of session_id() from string to int64_t.

BUG=webrtc:7311
==========

to

==========
Change the type of session_id() from string to int64_t.

BUG=webrtc:7311

Review-Url: https://codereview.webrtc.org/2749493002
Cr-Commit-Position: refs/heads/master@{#17215}
Committed:
https://chromium.googlesource.com/external/webrtc/+/30e0da4a65d4ded14a9158b61...
==========

[commit-bot: I haz the power, 2017-03-13 18:00:58]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/external/webrtc/+/30e0da4a65d4ded14a9158b61...