module.exports should default to an empty object.

module.exports should default to an empty object.

Per the spec in modules.md the exports property should default to an
empty object. We lazy allocate it so that modules that just replace it
don't create the empty object and then throw it away.

R=abarth@chromium.org

Committed: https://chromium.googlesource.com/external/mojo/+/670cc46fb1c30d9450ec5f61963ab92c659d3c43

[esprehn, 2015-01-24 01:13:21]

esprehn@chromium.org changed reviewers:
+ abarth@chromium.org

[abarth-chromium, 2015-01-24 05:13:15]

lgtm

[esprehn, 2015-01-26 19:38:08]

Committed patchset #1 (id:1) manually as
670cc46fb1c30d9450ec5f61963ab92c659d3c43 (presubmit successful).