[runtime] Support proxies as return value of API constructors.

[runtime] Support proxies as return value of API constructors.

When a FunctionTemplate-based function is used as a constructor
and returns a JSProxy, we incorrectly treated that result the same
as a non-object result. Now it is treated like any other object
result, i.e., it becomes the result of the constructor call.

R=verwaest@chromium.org
BUG=v8:6294
Review-Url: https://codereview.chromium.org/2845123002
Cr-Commit-Position: refs/heads/master@{#44970}
Committed: https://chromium.googlesource.com/v8/v8/+/9bfb0fef08a4170899a44487911c0dc78b4985e2

[neis, 2017-04-27 18:54:26]

Description was changed from

==========
[runtime] Support proxies as return value of API constructors.

R=verwaest@chromium.org
BUG=v8:6294
==========

to

==========
[runtime] Support proxies as return value of API constructors.

When a FunctionTemplate-based function is used as a constructor
and returns a JSProxy, we incorrectly treated that result the same
as a non-object result. Now it is treated like any other object
result, i.e., it becomes the result of the constructor call.

R=verwaest@chromium.org
BUG=v8:6294
==========

[Toon Verwaest, 2017-04-28 09:16:44]

lgtm

[neis, 2017-04-28 09:30:05]

The CQ bit was checked by neis@chromium.org

[commit-bot: I haz the power, 2017-04-28 09:30:10]

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, 2017-04-28 10:02:28]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1493371805470860, "parent_rev":
"0655ee8fa1864ae9b735d67828bcefa5633faf9e", "commit_rev":
"9bfb0fef08a4170899a44487911c0dc78b4985e2"}

[commit-bot: I haz the power, 2017-04-28 10:02:35]

Description was changed from

==========
[runtime] Support proxies as return value of API constructors.

When a FunctionTemplate-based function is used as a constructor
and returns a JSProxy, we incorrectly treated that result the same
as a non-object result. Now it is treated like any other object
result, i.e., it becomes the result of the constructor call.

R=verwaest@chromium.org
BUG=v8:6294
==========

to

==========
[runtime] Support proxies as return value of API constructors.

When a FunctionTemplate-based function is used as a constructor
and returns a JSProxy, we incorrectly treated that result the same
as a non-object result. Now it is treated like any other object
result, i.e., it becomes the result of the constructor call.

R=verwaest@chromium.org
BUG=v8:6294

Review-Url: https://codereview.chromium.org/2845123002
Cr-Commit-Position: refs/heads/master@{#44970}
Committed:
https://chromium.googlesource.com/v8/v8/+/9bfb0fef08a4170899a44487911c0dc78b4...
==========

[commit-bot: I haz the power, 2017-04-28 10:02:36]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/v8/v8/+/9bfb0fef08a4170899a44487911c0dc78b4...