Set listener task runner before connect channel.

Set listener task runner before connect channel.

Renderer main thread will run ChannelProxy::SetListenerTaskRunner()
to set listener task runner, but the task runner may be accessed on
IPC thread at the same time.
This CL is to fix the race condition.

TBR=nasko@chromium.org
BUG=479684
Committed: https://crrev.com/2c0f9f1c87c48b03dc4ef3582f724fcfff389a52
Cr-Commit-Position: refs/heads/master@{#338425}

[leonhsl(Using Gerrit), 2015-07-09 09:05:47]

PTAL, Thanks in advance~

[leonhsl(Using Gerrit), 2015-07-10 03:38:44]

leon.han@intel.com changed reviewers:
+ halton.huo@intel.com

[leonhsl(Using Gerrit), 2015-07-10 03:38:45]

Added change for browser_tests.

[nasko, 2015-07-10 09:06:06]

nasko@chromium.org changed reviewers:
+ avi@chromium.org

[nasko, 2015-07-10 09:06:06]

Hey Avi,
Can you take this one?
Thanks in advance!

[Avi (use Gerrit), 2015-07-10 15:44:46]

lgtm

[leonhsl(Using Gerrit), 2015-07-10 16:12:01]

The CQ bit was checked by leon.han@intel.com

[commit-bot: I haz the power, 2015-07-10 16:12:09]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1227303002/40001

[commit-bot: I haz the power, 2015-07-10 16:25:57]

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

[commit-bot: I haz the power, 2015-07-10 16:25:58]

Try jobs failed on following builders:
  linux_chromium_gn_rel on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

(exceeded global retry quota)

[leonhsl(Using Gerrit), 2015-07-10 16:33:20]

The CQ bit was checked by leon.han@intel.com to run a CQ dry run

[leonhsl(Using Gerrit), 2015-07-10 16:33:21]

The patchset sent to the CQ was uploaded after l-g-t-m from avi@chromium.org
Link to the patchset: https://codereview.chromium.org/1227303002/#ps50008
(title: "Fix trybot error.")

[commit-bot: I haz the power, 2015-07-10 16:33:45]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1227303002/50008

[commit-bot: I haz the power, 2015-07-10 17:24:56]

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

[commit-bot: I haz the power, 2015-07-10 17:24:57]

Dry run: This issue passed the CQ dry run.

[leonhsl(Using Gerrit), 2015-07-11 01:56:48]

The CQ bit was checked by leon.han@intel.com

[commit-bot: I haz the power, 2015-07-11 01:57:04]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1227303002/50008

[commit-bot: I haz the power, 2015-07-11 02:01:26]

Committed patchset #4 (id:50008)

[commit-bot: I haz the power, 2015-07-11 02:02:24]

Patchset 4 (id:??) landed as
https://crrev.com/2c0f9f1c87c48b03dc4ef3582f724fcfff389a52
Cr-Commit-Position: refs/heads/master@{#338425}