[mdv] Avoid observing placeholder arrays in TemplateIterator

Avoid observing placeholder arrays in TemplateIterator
... and minimize instance removal/addition

port of https://github.com/Polymer/mdv/commit/1bc8afff957fc542ac5925afd8575dce229be835

I also rolled a few other parts of TemplateIterator forward to be based on current code.

The list_diff port is from change_summary.js. It was ported and reviewed in an older MDV CL, but not checked in because ObservableList is smarter about producing diffs.

R=justinfagnani@google.com

Committed: https://code.google.com/p/dart/source/detail?r=25392

[Jennifer Messerly, 2013-07-23 20:35:34]

+Siggi too. Since you had reviewed the list_diff.dart file previously :)

[justinfagnani, 2013-07-24 00:42:55]

lgtm

https://chromiumcodereview.appspot.com/19492018/diff/1/pkg/mdv/lib/src/input_...
File pkg/mdv/lib/src/input_bindings.dart (right):

https://chromiumcodereview.appspot.com/19492018/diff/1/pkg/mdv/lib/src/input_...
pkg/mdv/lib/src/input_bindings.dart:157: // Instead we use runAsync. Each
<template repeat> needs a delay of 3:
3 -> 2?

https://chromiumcodereview.appspot.com/19492018/diff/1/pkg/mdv/lib/src/templa...
File pkg/mdv/lib/src/template_iterator.dart (right):

https://chromiumcodereview.appspot.com/19492018/diff/1/pkg/mdv/lib/src/templa...
pkg/mdv/lib/src/template_iterator.dart:189: inputs = new
CompoundBinding(resolveInputs);
why remove this from the initializer list, or make it non-final? I don't see an
assignment in the changes here.

https://chromiumcodereview.appspot.com/19492018/diff/1/pkg/mdv/lib/src/templa...
pkg/mdv/lib/src/template_iterator.dart:192: resolveInputs(Map values) {
void?

https://chromiumcodereview.appspot.com/19492018/diff/1/pkg/mdv/lib/src/templa...
pkg/mdv/lib/src/template_iterator.dart:207: if (value is! List) value = null;
when do we want to use Iterable over List?

[Jennifer Messerly, 2013-07-24 00:52:58]

Thanks!

https://chromiumcodereview.appspot.com/19492018/diff/1/pkg/mdv/lib/src/input_...
File pkg/mdv/lib/src/input_bindings.dart (right):

https://chromiumcodereview.appspot.com/19492018/diff/1/pkg/mdv/lib/src/input_...
pkg/mdv/lib/src/input_bindings.dart:157: // Instead we use runAsync. Each
<template repeat> needs a delay of 3:
On 2013/07/24 00:42:55, justinfagnani wrote:
> 3 -> 2?

Done.

https://chromiumcodereview.appspot.com/19492018/diff/1/pkg/mdv/lib/src/templa...
File pkg/mdv/lib/src/template_iterator.dart (right):

https://chromiumcodereview.appspot.com/19492018/diff/1/pkg/mdv/lib/src/templa...
pkg/mdv/lib/src/template_iterator.dart:189: inputs = new
CompoundBinding(resolveInputs);
On 2013/07/24 00:42:55, justinfagnani wrote:
> why remove this from the initializer list, or make it non-final? I don't see
an
> assignment in the changes here.

it's sneaky: resolveInputs is no longer static, so we can't access it from an
initializer in Dart

https://chromiumcodereview.appspot.com/19492018/diff/1/pkg/mdv/lib/src/templa...
pkg/mdv/lib/src/template_iterator.dart:192: resolveInputs(Map values) {
On 2013/07/24 00:42:55, justinfagnani wrote:
> void?

Done.

https://chromiumcodereview.appspot.com/19492018/diff/1/pkg/mdv/lib/src/templa...
pkg/mdv/lib/src/template_iterator.dart:207: if (value is! List) value = null;
On 2013/07/24 00:42:55, justinfagnani wrote:
> when do we want to use Iterable over List?

good question. I think we should follow up with MDV about this.

offhand, it definitely needs indexing for some of the operations, but we could
call .toList(). However I'm not sure if the typical Iterable is going to
implement observability (or how you would define it without indexes).

[Jennifer Messerly, 2013-07-24 01:06:55]

https://chromiumcodereview.appspot.com/19492018/diff/1/pkg/mdv/lib/src/templa...
File pkg/mdv/lib/src/template_iterator.dart (right):

https://chromiumcodereview.appspot.com/19492018/diff/1/pkg/mdv/lib/src/templa...
pkg/mdv/lib/src/template_iterator.dart:192: resolveInputs(Map values) {
On 2013/07/24 00:52:58, John Messerly wrote:
> On 2013/07/24 00:42:55, justinfagnani wrote:
> > void?
> 
> Done.

update: it actually can't be void... CompoundBinding expects a value. I've
changed it to explicitly return null and added a comment

[Jennifer Messerly, 2013-07-24 01:11:11]

Committed patchset #2 manually as r25392 (presubmit successful).

[Siggi Cherem (dart-lang), 2013-07-24 17:17:55]

lgtm