DevTools: [SASS] implement AST differ.

DevTools: [SASS] implement AST differ.

The patch implements WI.SASSSupport.diffModels method, which computes
diff of two AST models.

The current implementation doesn't handle rule diff, i.e. adding
and removing rules, or modification of rule selectors.

BUG=527993
R=pfeldman

Committed: https://crrev.com/7df97a0f55fea2e954b4eee19e7944c563f9d036
Cr-Commit-Position: refs/heads/master@{#364463}

[lushnikov, 2015-12-10 08:00:55]

ptal

[pfeldman, 2015-12-10 19:18:38]

lgtm

[lushnikov, 2015-12-10 19:19:08]

The CQ bit was checked by lushnikov@chromium.org

[commit-bot: I haz the power, 2015-12-10 19:20:53]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1504923008/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1504923008/1

[commit-bot: I haz the power, 2015-12-10 20:41:03]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-12-10 20:42:53]

Description was changed from

==========
DevTools: [SASS] implement AST differ.

The patch implements WI.SASSSupport.diffModels method, which computes
diff of two AST models.

The current implementation doesn't handle rule diff, i.e. adding
and removing rules, or modification of rule selectors.

BUG=527993
R=pfeldman
==========

to

==========
DevTools: [SASS] implement AST differ.

The patch implements WI.SASSSupport.diffModels method, which computes
diff of two AST models.

The current implementation doesn't handle rule diff, i.e. adding
and removing rules, or modification of rule selectors.

BUG=527993
R=pfeldman

Committed: https://crrev.com/7df97a0f55fea2e954b4eee19e7944c563f9d036
Cr-Commit-Position: refs/heads/master@{#364463}
==========

[commit-bot: I haz the power, 2015-12-10 20:42:54]

Patchset 1 (id:??) landed as
https://crrev.com/7df97a0f55fea2e954b4eee19e7944c563f9d036
Cr-Commit-Position: refs/heads/master@{#364463}