[es6] Implement Date.prototype[@@toPrimitive] as C++ builtin.

[es6] Implement Date.prototype[@@toPrimitive] as C++ builtin.

This way we don't need to expose JSReceiver::OrdinaryToPrimitive
as runtime function, and we don't need the separate JS trampoline.

This also adds tests for ToPrimitive on date objects, which are
special.

R=mstarzinger@chromium.org
BUG=v8:4307
LOG=n

Committed: https://crrev.com/3c164506f566ad99016f80c21caa56c060e3e262
Cr-Commit-Position: refs/heads/master@{#30473}

[Benedikt Meurer, 2015-08-31 11:45:26]

PTAL

[Michael Starzinger, 2015-08-31 12:12:57]

LGTM.

https://codereview.chromium.org/1324713002/diff/1/src/objects.h
File src/objects.h (right):

https://codereview.chromium.org/1324713002/diff/1/src/objects.h#newcode176
src/objects.h:176: // Valid hints for the abstract operations
OrdinaryToPrimitive,
nit: s/operations/operation/

https://codereview.chromium.org/1324713002/diff/20001/src/objects.cc
File src/objects.cc (right):

https://codereview.chromium.org/1324713002/diff/20001/src/objects.cc#newcode8371
src/objects.cc:8371: name_string[description_length + 1] = ']';
This string construction looks scarry if {name} were to be controlled by user
code. I assume this will only be used on names that we control?

[Benedikt Meurer, 2015-08-31 12:26:48]

Addressed feedback. Thanks.

https://codereview.chromium.org/1324713002/diff/1/src/objects.h
File src/objects.h (right):

https://codereview.chromium.org/1324713002/diff/1/src/objects.h#newcode176
src/objects.h:176: // Valid hints for the abstract operations
OrdinaryToPrimitive,
On 2015/08/31 12:12:57, Michael Starzinger wrote:
> nit: s/operations/operation/

Done.

https://codereview.chromium.org/1324713002/diff/20001/src/objects.cc
File src/objects.cc (right):

https://codereview.chromium.org/1324713002/diff/20001/src/objects.cc#newcode8371
src/objects.cc:8371: name_string[description_length + 1] = ']';
Changed this to MaybeHandle and use IncrementalStringBuilder

[Benedikt Meurer, 2015-08-31 12:26:53]

The CQ bit was checked by bmeurer@chromium.org

[Benedikt Meurer, 2015-08-31 12:26:54]

The patchset sent to the CQ was uploaded after l-g-t-m from
mstarzinger@chromium.org
Link to the patchset: https://codereview.chromium.org/1324713002/#ps40001
(title: "Address Michi's comments.")

[commit-bot: I haz the power, 2015-08-31 12:27:00]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1324713002/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1324713002/40001

[commit-bot: I haz the power, 2015-08-31 12:53:06]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2015-08-31 12:53:17]

Patchset 3 (id:??) landed as
https://crrev.com/3c164506f566ad99016f80c21caa56c060e3e262
Cr-Commit-Position: refs/heads/master@{#30473}