[modules] Store Module metadata in per-Context EmbedderData

[modules] Store Module metadata in per-Context EmbedderData

This is a re-land of https://codereview.chromium.org/2393303002/ with
an additional call to DisposeModuleEmbedderData() added to fix lsan failures.

Unifies the approaches used for storing the specifier -> module mapping
and the module -> directory mapping, using std::unordered_maps for both
and storing them per-Context.

This requires adding a method to the v8::Module API to get a hash code
for a Module, but allows slimming down the API in return: gone are
SetEmbedderData/GetEmbedderData, along with the fourth argument
to ResolveModuleCallback.

Besides a simpler API, this allows d8 to get closer to the HTML loader,
which requires each Realm to have a persistent module map (though this
capability is not yet exercised by any tests).

BUG=v8:1569
TBR=neis@chromium.org,jochen@chromium.org

Committed: https://crrev.com/9d2051fc2896bcb771cfb41b2864601c6c40e299
Cr-Commit-Position: refs/heads/master@{#40186}

[adamk, 2016-10-11 18:25:26]

The CQ bit was checked by adamk@chromium.org

[commit-bot: I haz the power, 2016-10-11 18:25:35]

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, 2016-10-11 19:22:11]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2016-10-11 19:22:33]

Description was changed from

==========
[modules] Store Module metadata in per-Context EmbedderData

This is a re-land of https://codereview.chromium.org/2393303002/ with
an additional call to DisposeModuleEmbedderData() added to fix lsan failures.

Unifies the approaches used for storing the specifier -> module mapping
and the module -> directory mapping, using std::unordered_maps for both
and storing them per-Context.

This requires adding a method to the v8::Module API to get a hash code
for a Module, but allows slimming down the API in return: gone are
SetEmbedderData/GetEmbedderData, along with the fourth argument
to ResolveModuleCallback.

Besides a simpler API, this allows d8 to get closer to the HTML loader,
which requires each Realm to have a persistent module map (though this
capability is not yet exercised by any tests).

BUG=v8:1569
TBR=neis@chromium.org,jochen@chromium.org
==========

to

==========
[modules] Store Module metadata in per-Context EmbedderData

This is a re-land of https://codereview.chromium.org/2393303002/ with
an additional call to DisposeModuleEmbedderData() added to fix lsan failures.

Unifies the approaches used for storing the specifier -> module mapping
and the module -> directory mapping, using std::unordered_maps for both
and storing them per-Context.

This requires adding a method to the v8::Module API to get a hash code
for a Module, but allows slimming down the API in return: gone are
SetEmbedderData/GetEmbedderData, along with the fourth argument
to ResolveModuleCallback.

Besides a simpler API, this allows d8 to get closer to the HTML loader,
which requires each Realm to have a persistent module map (though this
capability is not yet exercised by any tests).

BUG=v8:1569
TBR=neis@chromium.org,jochen@chromium.org

Committed: https://crrev.com/9d2051fc2896bcb771cfb41b2864601c6c40e299
Cr-Commit-Position: refs/heads/master@{#40186}
==========

[commit-bot: I haz the power, 2016-10-11 19:22:34]

Patchset 3 (id:??) landed as
https://crrev.com/9d2051fc2896bcb771cfb41b2864601c6c40e299
Cr-Commit-Position: refs/heads/master@{#40186}