Improve the names used in Mojo JS modules

Improve the names used in Mojo JS modules

Previously, we just used ugly numbered names as the local names for modules in
JavaScript. Now we try to use a meaningful name based on the name of the
module.

There shouldn't be any behavior change.

R=hansmuller@chromium.org

Committed: https://crrev.com/32c970a8e690342135e35f043fcee5330c811027
Cr-Commit-Position: refs/heads/master@{#299413}

[hansmuller, 2014-10-14 00:08:08]

This LGTM.  Glad to see importN go away.

[abarth-chromium, 2014-10-14 01:00:12]

By the way, I noticed in writing this CL that many of these imports aren't
actually referenced by the generated JavaScript.  Do you think it would be
valuable to try to prune the import list to just those that are actually used?

[abarth-chromium, 2014-10-14 01:00:16]

The CQ bit was checked by abarth@chromium.org

[commit-bot: I haz the power, 2014-10-14 01:02:02]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/653793002/1

[commit-bot: I haz the power, 2014-10-14 01:24:50]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-10-14 01:25:31]

Patchset 1 (id:??) landed as
https://crrev.com/32c970a8e690342135e35f043fcee5330c811027
Cr-Commit-Position: refs/heads/master@{#299413}