[js2c] Fix ordering issue of TextMacro expansion

[js2c] Fix ordering issue of TextMacro expansion

If a key is a substring of an earlier value, then the earlier value
will unintentionally be clobbered. For example with:
  macro SET_PRIVATE(obj, sym, val) = (obj[sym] = val);
  SET_PRIVATE(iterator, arrayIteratorObjectSymbol, object);
if the mapping is:
  {'val': 'object',
   'obj': 'iterator',
   'sym': 'arrayIteratorObjectSymbol'}
then 'obj' -> 'iterator' will clobber 'val' -> 'object', resulting in
'val' -> 'iteratorect'. To fix this, replace all substitutions
simultaneously.

Patch from Zoe Clifford <zoeclifford@google.com>;

Committed: https://crrev.com/95db63ab6b87415e17eadc5b7caf7efbc3217e76
Cr-Commit-Position: refs/heads/master@{#38665}

[Jakob Kummerow, 2016-08-16 13:55:26]

jkummerow@chromium.org changed reviewers:
+ littledan@chromium.org

[Jakob Kummerow, 2016-08-16 13:55:26]

Dan: PTAL.

Yang, Zoe: FYI.

Sure would be nice if we had test coverage of js2c.py, eh? I've tested this
locally as follows:

t = js2c.TextMacro(["foo"], "hello foo")
t.expand({'foo': 'World', 'o': 'a'})

Before patch: 'hella Warld'
After patch:  'hella World'

[Dan Ehrenberg, 2016-08-16 15:03:52]

lgtm

This is great! I think I've run into this bug as well.

[Jakob Kummerow, 2016-08-16 16:28:23]

The CQ bit was checked by jkummerow@chromium.org

[commit-bot: I haz the power, 2016-08-16 16:28:32]

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, 2016-08-16 16:51:24]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-08-16 16:51:51]

Description was changed from

==========
[js2c] Fix ordering issue of TextMacro expansion

If a key is a substring of an earlier value, then the earlier value
will unintentionally be clobbered. For example with:
  macro SET_PRIVATE(obj, sym, val) = (obj[sym] = val);
  SET_PRIVATE(iterator, arrayIteratorObjectSymbol, object);
if the mapping is:
  {'val': 'object',
   'obj': 'iterator',
   'sym': 'arrayIteratorObjectSymbol'}
then 'obj' -> 'iterator' will clobber 'val' -> 'object', resulting in
'val' -> 'iteratorect'. To fix this, replace all substitutions
simultaneously.

Patch from Zoe Clifford <zoeclifford@google.com>
==========

to

==========
[js2c] Fix ordering issue of TextMacro expansion

If a key is a substring of an earlier value, then the earlier value
will unintentionally be clobbered. For example with:
  macro SET_PRIVATE(obj, sym, val) = (obj[sym] = val);
  SET_PRIVATE(iterator, arrayIteratorObjectSymbol, object);
if the mapping is:
  {'val': 'object',
   'obj': 'iterator',
   'sym': 'arrayIteratorObjectSymbol'}
then 'obj' -> 'iterator' will clobber 'val' -> 'object', resulting in
'val' -> 'iteratorect'. To fix this, replace all substitutions
simultaneously.

Patch from Zoe Clifford <zoeclifford@google.com>

Committed: https://crrev.com/95db63ab6b87415e17eadc5b7caf7efbc3217e76
Cr-Commit-Position: refs/heads/master@{#38665}
==========

[commit-bot: I haz the power, 2016-08-16 16:51:51]

Patchset 1 (id:??) landed as
https://crrev.com/95db63ab6b87415e17eadc5b7caf7efbc3217e76
Cr-Commit-Position: refs/heads/master@{#38665}