fix nested bindings in polymer_expressions

fix nested bindings

R=sigmund@google.com

Committed: https://code.google.com/p/dart/source/detail?r=29722

[Jennifer Messerly, 2013-11-01 01:40:08]

pretty simple fix -- for empty paths (e.g. <template bind> which is essentially
<template bind="{{}}">), PolymerExpressions will (correctly) unwrap its Scope,
since users should never see Scopes. But <template bind> itself goes through
that logic, so the variables get thrown away as soon as you have a template
nested inside another template.

The fix is to keep Scope around if we're just binding to a template property. I
dunno if this fix is really correct long term (Scope should never leak into a
user-visible model), but it seems good enough for now.

FWIW, the JS impl uses an Expando which is probably better. Hides this
implementation detail completely.

[Siggi Cherem (dart-lang), 2013-11-01 01:54:32]

lgtm

https://codereview.chromium.org/51953012/diff/70001/pkg/polymer/test/nested_b...
File pkg/polymer/test/nested_binding_test.dart (right):

https://codereview.chromium.org/51953012/diff/70001/pkg/polymer/test/nested_b...
pkg/polymer/test/nested_binding_test.dart:35: reflectClass(String); // so we can
call string.length
didn't know this was also a hint for dart2js. Is this expressible with
@MirrorsUsed ?

https://codereview.chromium.org/51953012/diff/70001/pkg/polymer/test/nested_b...
pkg/polymer/test/nested_binding_test.dart:43: (query('my-test') as
MyTest)._testDone.future as Future);
remove as Future?

[Jennifer Messerly, 2013-11-01 02:14:56]

https://codereview.chromium.org/51953012/diff/70001/pkg/polymer/test/nested_b...
File pkg/polymer/test/nested_binding_test.dart (right):

https://codereview.chromium.org/51953012/diff/70001/pkg/polymer/test/nested_b...
pkg/polymer/test/nested_binding_test.dart:35: reflectClass(String); // so we can
call string.length
On 2013/11/01 01:54:33, Siggi Cherem (dart-lang) wrote:
> didn't know this was also a hint for dart2js. Is this expressible with
> @MirrorsUsed ?

clarified comment. this line doesn't do anything, I'm just using mirrors so
editor doesn't complain :). it's the "import mirrors" up top that pulls in
String.length

https://codereview.chromium.org/51953012/diff/70001/pkg/polymer/test/nested_b...
pkg/polymer/test/nested_binding_test.dart:43: (query('my-test') as
MyTest)._testDone.future as Future);
On 2013/11/01 01:54:33, Siggi Cherem (dart-lang) wrote:
> remove as Future?

good catch :)

[Jennifer Messerly, 2013-11-01 02:15:21]

Committed patchset #5 manually as r29722 (presubmit successful).

[kasperl, 2013-11-01 08:46:15]

This is causing redness on the build bots. Reverting.