Revert of Messaging: Avoid calling non-thread-safe functions in MessagePort::messageAvailable()

Revert of Messaging: Avoid calling non-thread-safe functions in MessagePort::messageAvailable() (patchset #2 id:20001 of https://codereview.chromium.org/2818073002/ )

Reason for revert:
[1] that this CL depends on needs to be reverted:
https://codereview.chromium.org/2831843002/

Original issue's description:
> Messaging: Avoid calling non-thread-safe functions in MessagePort::messageAvailable()
> 
> As implementation comments in MessagePort::messageAvailable(), it can be called
> from another thread and should not call non-thread-functions. However, the
> current implementation wrongly calls ContextLifecycleObserver's
> GetExecutionContext() that is not a thread-safe function to post a task to the
> context thread.
> 
> To avoid that, this CL replaces ExecutionContext::PostTask() with
> WebTaskRunner::PostTask(). The task runner is captured in the ctor of
> MessagePort called on the context thread.
> 
> BUG=694925
> 
> Review-Url: https://codereview.chromium.org/2818073002
> Cr-Commit-Position: refs/heads/master@{#465886}
> Committed: https://chromium.googlesource.com/chromium/src/+/829907ac0d3d2ed39d8752d22a6d0e45df1e8325

TBR=tzik@chromium.org,yuryu@chromium.org,kinuko@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=694925
Review-Url: https://codereview.chromium.org/2833673002
Cr-Commit-Position: refs/heads/master@{#465890}
Committed: https://chromium.googlesource.com/chromium/src/+/7cbe41ace5629ba6b9ec5502803f02fb2f09b0fd

[nhiroki, 2017-04-20 03:40:05]

The CQ bit was checked by nhiroki@chromium.org

[nhiroki, 2017-04-20 03:40:06]

Created Revert of Messaging: Avoid calling non-thread-safe functions in
MessagePort::messageAvailable()

[commit-bot: I haz the power, 2017-04-20 03:40:18]

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

[commit-bot: I haz the power, 2017-04-20 03:40:41]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1492659605899070, "parent_rev":
"43bd95af39ce6dc2c2ac11d70a1fbff816ef0794", "commit_rev":
"7cbe41ace5629ba6b9ec5502803f02fb2f09b0fd"}

[commit-bot: I haz the power, 2017-04-20 03:40:52]

Description was changed from

==========
Revert of Messaging: Avoid calling non-thread-safe functions in
MessagePort::messageAvailable() (patchset #2 id:20001 of
https://codereview.chromium.org/2818073002/ )

Reason for revert:
[1] that this CL depends on needs to be reverted:
https://codereview.chromium.org/2831843002/

Original issue's description:
> Messaging: Avoid calling non-thread-safe functions in
MessagePort::messageAvailable()
> 
> As implementation comments in MessagePort::messageAvailable(), it can be
called
> from another thread and should not call non-thread-functions. However, the
> current implementation wrongly calls ContextLifecycleObserver's
> GetExecutionContext() that is not a thread-safe function to post a task to the
> context thread.
> 
> To avoid that, this CL replaces ExecutionContext::PostTask() with
> WebTaskRunner::PostTask(). The task runner is captured in the ctor of
> MessagePort called on the context thread.
> 
> BUG=694925
> 
> Review-Url: https://codereview.chromium.org/2818073002
> Cr-Commit-Position: refs/heads/master@{#465886}
> Committed:
https://chromium.googlesource.com/chromium/src/+/829907ac0d3d2ed39d8752d22a6d...

TBR=tzik@chromium.org,yuryu@chromium.org,kinuko@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=694925
==========

to

==========
Revert of Messaging: Avoid calling non-thread-safe functions in
MessagePort::messageAvailable() (patchset #2 id:20001 of
https://codereview.chromium.org/2818073002/ )

Reason for revert:
[1] that this CL depends on needs to be reverted:
https://codereview.chromium.org/2831843002/

Original issue's description:
> Messaging: Avoid calling non-thread-safe functions in
MessagePort::messageAvailable()
> 
> As implementation comments in MessagePort::messageAvailable(), it can be
called
> from another thread and should not call non-thread-functions. However, the
> current implementation wrongly calls ContextLifecycleObserver's
> GetExecutionContext() that is not a thread-safe function to post a task to the
> context thread.
> 
> To avoid that, this CL replaces ExecutionContext::PostTask() with
> WebTaskRunner::PostTask(). The task runner is captured in the ctor of
> MessagePort called on the context thread.
> 
> BUG=694925
> 
> Review-Url: https://codereview.chromium.org/2818073002
> Cr-Commit-Position: refs/heads/master@{#465886}
> Committed:
https://chromium.googlesource.com/chromium/src/+/829907ac0d3d2ed39d8752d22a6d...

TBR=tzik@chromium.org,yuryu@chromium.org,kinuko@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=694925

Review-Url: https://codereview.chromium.org/2833673002
Cr-Commit-Position: refs/heads/master@{#465890}
Committed:
https://chromium.googlesource.com/chromium/src/+/7cbe41ace5629ba6b9ec5502803f...
==========

[commit-bot: I haz the power, 2017-04-20 03:40:53]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/7cbe41ace5629ba6b9ec5502803f...

[nhiroki, 2017-04-20 23:01:46]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/2836473002/ by nhiroki@chromium.org.

The reason for reverting is: The CL that this CL depends on was relanded:
https://codereview.chromium.org/2832763002/.