[Binding][PerformanceTest] Fix post-message.html to wait messages' responses.

Fix the behavior of post-message.html

Before this CL, the test sent 10k messages and finished.
In this style, we had two issues;
1. it did not measure performance of postMessage
2. it remained many message tasks in pool, and regressed following tests.

This CL makes it to wait all messages' responses arrives,
and fixes the issues.

BUG=601832
Committed: https://crrev.com/e3fe1b6186a589a8f5d020b2e4d8eaee8fe48ddd
Cr-Commit-Position: refs/heads/master@{#389430}

[peria, 2016-04-25 05:10:38]

Patchset #1 (id:1) has been deleted

[peria, 2016-04-25 05:16:39]

Description was changed from

==========
Fix post-message.html to wait messages' responses.

BUG=601832
==========

to

==========
Fix the behavior of post-message.html

Before this CL, the test sent 10k messages and finished.
In this style, we had two issues;
1. it did not measure performance of postMessage
2. it remained many message tasks in pool, and regressed following tests.

This CL makes it to wait all messages' responses arrives,
and fixes the issues.


BUG=601832
==========

[peria, 2016-04-25 05:17:20]

peria@chromium.org changed reviewers:
+ yukishiino@chromium.org

[peria, 2016-04-25 05:17:20]

PTL

[Yuki, 2016-04-25 05:37:00]

lgtm

[peria, 2016-04-25 05:39:16]

The CQ bit was checked by peria@chromium.org

[commit-bot: I haz the power, 2016-04-25 05:39:28]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1921503002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1921503002/20001

[commit-bot: I haz the power, 2016-04-25 08:17:22]

Description was changed from

==========
Fix the behavior of post-message.html

Before this CL, the test sent 10k messages and finished.
In this style, we had two issues;
1. it did not measure performance of postMessage
2. it remained many message tasks in pool, and regressed following tests.

This CL makes it to wait all messages' responses arrives,
and fixes the issues.


BUG=601832
==========

to

==========
Fix the behavior of post-message.html

Before this CL, the test sent 10k messages and finished.
In this style, we had two issues;
1. it did not measure performance of postMessage
2. it remained many message tasks in pool, and regressed following tests.

This CL makes it to wait all messages' responses arrives,
and fixes the issues.


BUG=601832
==========

[commit-bot: I haz the power, 2016-04-25 08:17:23]

Committed patchset #1 (id:20001)

[commit-bot: I haz the power, 2016-04-25 08:18:30]

Description was changed from

==========
Fix the behavior of post-message.html

Before this CL, the test sent 10k messages and finished.
In this style, we had two issues;
1. it did not measure performance of postMessage
2. it remained many message tasks in pool, and regressed following tests.

This CL makes it to wait all messages' responses arrives,
and fixes the issues.


BUG=601832
==========

to

==========
Fix the behavior of post-message.html

Before this CL, the test sent 10k messages and finished.
In this style, we had two issues;
1. it did not measure performance of postMessage
2. it remained many message tasks in pool, and regressed following tests.

This CL makes it to wait all messages' responses arrives,
and fixes the issues.

BUG=601832

Committed: https://crrev.com/e3fe1b6186a589a8f5d020b2e4d8eaee8fe48ddd
Cr-Commit-Position: refs/heads/master@{#389430}
==========

[commit-bot: I haz the power, 2016-04-25 08:18:31]

Patchset 1 (id:??) landed as
https://crrev.com/e3fe1b6186a589a8f5d020b2e4d8eaee8fe48ddd
Cr-Commit-Position: refs/heads/master@{#389430}