fix jstemplate_builder::UseVersion2

fix jstemplate_builder::UseVersion2

realized the old implementation was over-complicated and could fail if two objects had interleaved, rather than nested, scope.

BUG=none
TEST=manual


Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=134663

[Evan Stade, 2012-04-30 23:37:39]

for example, this wouldn't have worked (not sure why you'd want to do it anyway
though):

scoped_ptr<UseVersion2> version(new UseVersion2);
version.reset(new UseVersion2);
version.reset();

as it would have left g_version2 stuck on true.

[Dan Beam, 2012-05-01 00:14:18]

lgtm after explanation of all of Chrome, :) (thank you for this)

[commit-bot: I haz the power, 2012-05-01 00:20:14]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/estade@chromium.org/10269008/1

[commit-bot: I haz the power, 2012-05-01 01:55:58]

Change committed as 134663