[ES6 modules] FetchDescendants: skip fetch algorithm for descendants that are already ready

[ES6 modules] FetchDescendants: skip fetch algorithm for descendants that are already ready

Before this CL, we triggered #internal-module-graph-fetch-procedure for
descendants which we already had its entry in the module map.

This CL skips issuing #internal-module-graph-fetch-procedure for those descendants
which we could find its "instantiated" module script entry on module map.
This speeds up module tree fetch performance by reducing number of asynchronous
tasks which has non-trivial overhead. This CL avoids the ModuleTreeLinker to
wait on the asynchronous completion calls which will just complete immediately for
"instantiated" module script tree.

BUG=594639, 722728, 740874

[kouhei (in TOK), 2017-05-16 20:40:18]

The CQ bit was checked by kouhei@chromium.org to run a CQ dry run

[kouhei (in TOK), 2017-05-16 20:40:50]

Description was changed from

==========
[ES6 modules] FetchDescendants: skip fetch algorithm for descendants that are
already ready

Before this CL, we triggered #internal-module-graph-fetch-procedure for
descendants which we already had its entry in the module map.

This CL skips issuing #internal-module-graph-fetch-procedure for those
descendants
which we could find its "instantiated" module script entry on module map.
This speeds up module tree fetch performance by reducing number of asynchronous
tasks which has non-trivial overhead. This CL avoids the ModuleTreeLinker to
wait on the asynchronous completion calls which will just complete immediately
for
"instantiated" module script tree.

BUG=594639, 716935
==========

to

==========
[ES6 modules] FetchDescendants: skip fetch algorithm for descendants that are
already ready

Before this CL, we triggered #internal-module-graph-fetch-procedure for
descendants which we already had its entry in the module map.

This CL skips issuing #internal-module-graph-fetch-procedure for those
descendants
which we could find its "instantiated" module script entry on module map.
This speeds up module tree fetch performance by reducing number of asynchronous
tasks which has non-trivial overhead. This CL avoids the ModuleTreeLinker to
wait on the asynchronous completion calls which will just complete immediately
for
"instantiated" module script tree.

BUG=594639, 716935
==========

[kouhei (in TOK), 2017-05-16 20:40:50]

kouhei@chromium.org changed reviewers:
+ domenic@chromium.org, hiroshige@chromium.org, module-dev@chromium.org,
neis@chromium.org

[commit-bot: I haz the power, 2017-05-16 20:41:42]

Dry run: 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, 2017-05-17 04:34:04]

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

[commit-bot: I haz the power, 2017-05-17 04:34:05]

Dry run: Try jobs failed on following builders:
  win_chromium_rel_ng on master.tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_rel_...)

[adamk, 2017-07-19 01:21:45]

Description was changed from

==========
[ES6 modules] FetchDescendants: skip fetch algorithm for descendants that are
already ready

Before this CL, we triggered #internal-module-graph-fetch-procedure for
descendants which we already had its entry in the module map.

This CL skips issuing #internal-module-graph-fetch-procedure for those
descendants
which we could find its "instantiated" module script entry on module map.
This speeds up module tree fetch performance by reducing number of asynchronous
tasks which has non-trivial overhead. This CL avoids the ModuleTreeLinker to
wait on the asynchronous completion calls which will just complete immediately
for
"instantiated" module script tree.

BUG=594639, 716935
==========

to

==========
[ES6 modules] FetchDescendants: skip fetch algorithm for descendants that are
already ready

Before this CL, we triggered #internal-module-graph-fetch-procedure for
descendants which we already had its entry in the module map.

This CL skips issuing #internal-module-graph-fetch-procedure for those
descendants
which we could find its "instantiated" module script entry on module map.
This speeds up module tree fetch performance by reducing number of asynchronous
tasks which has non-trivial overhead. This CL avoids the ModuleTreeLinker to
wait on the asynchronous completion calls which will just complete immediately
for
"instantiated" module script tree.

BUG=594639, 722728, 740874
==========