Enable binding to CSS selectors

[DartBot]

<img src="https://avatars.githubusercontent.com/u/2152569?v=3" align="left" width="96" height="96"hspace="10"> Issue by blois
Originally opened as dart-lang/sdk#13886

---

I see a pattern in polymer.js of:

<foo-model id='foo'></foo-model>
<foo-consumer modelID='foo'></foo-consumer>

Where foo-consumer then resolves '#foo' in the document.

Would be much nicer if the following syntax could be used:

<foo-consumer model='{{$(#foo)}}'></foo-consumer>

And foo-consumer would get change events if that query selector happened to change.

The benefit of this is that foo-consumer can get it's model any way- via bindings, something programmatically setting it, or looking it up in the DOM.

[DartBot]

<img src="https://avatars.githubusercontent.com/u/1081711?v=3" align="left" width="48" height="48"hspace="10"> Comment by jmesserly

---

Removed Type-En label.
Added Type-Enhancement, Library-PolymerExpressions labels.

[DartBot]

<img src="https://avatars.githubusercontent.com/u/1081711?v=3" align="left" width="48" height="48"hspace="10"> Comment by jmesserly

---

@pete, file bug here?
https://github.com/Polymer/polymer-expressions

[DartBot]

<img src="https://avatars.githubusercontent.com/u/522948?v=3" align="left" width="48" height="48"hspace="10"> Comment by justinfagnani

---

I have some code sitting around that does almost exactly this. It's not integrated into polymer expressions, it just returns streams of elements that enter and exit the query. WIth the streams support in expressions, it might already work. I'll try it out.

[DartBot]

<img src="https://avatars.githubusercontent.com/u/2049220?v=3" align="left" width="48" height="48"hspace="10"> Comment by sigmundch

---

Added this to the Later milestone.

[DartBot]

<img src="https://avatars.githubusercontent.com/u/2049220?v=3" align="left" width="48" height="48"hspace="10"> Comment by sigmundch

---

Removed this from the Later milestone.
Added this to the M9 milestone.

[DartBot]

<img src="https://avatars.githubusercontent.com/u/8616782?v=3" align="left" width="48" height="48"hspace="10"> Comment by clayberg

---

Removed this from the M9 milestone.
Added this to the 1.1 milestone.

[DartBot]

<img src="https://avatars.githubusercontent.com/u/2049220?v=3" align="left" width="48" height="48"hspace="10"> Comment by sigmundch

---

Removed this from the 1.1 milestone.
Added this to the 1.2 milestone.

[DartBot]

<img src="https://avatars.githubusercontent.com/u/1081711?v=3" align="left" width="48" height="48"hspace="10"> Comment by jmesserly

---

Removed Area-Polymer label.
Added Area-Pkg, Pkg-PolymerExpressions labels.

[DartBot]

<img src="https://avatars.githubusercontent.com/u/1081711?v=3" align="left" width="48" height="48"hspace="10"> Comment by jmesserly

---

Removed Library-PolymerExpressions label.

[DartBot]

<img src="https://avatars.githubusercontent.com/u/2156198?v=3" align="left" width="48" height="48"hspace="10"> Comment by kasperl

---

Removed this from the 1.2 milestone.
Added this to the 1.6 milestone.

[DartBot]

<img src="https://avatars.githubusercontent.com/u/2049220?v=3" align="left" width="48" height="48"hspace="10"> Comment by sigmundch

---

Removed this from the 1.6 milestone.
Added this to the Later milestone.
Removed Priority-Unassigned label.
Added Priority-Low label.

[DartBot]

<img src="https://avatars.githubusercontent.com/u/2049220?v=3" align="left" width="48" height="48"hspace="10"> Comment by sigmundch

---

Added Polymer-P-2 label.

[DartBot]

<img src="https://avatars.githubusercontent.com/u/2049220?v=3" align="left" width="48" height="48"hspace="10"> Comment by sigmundch

---

Removed this from the Later milestone.

[DartBot]

<img src="https://avatars.githubusercontent.com/u/2049220?v=3" align="left" width="48" height="48"hspace="10"> Comment by sigmundch

---

Removed Polymer-P-2 label.
Added Polymer-Milestone-Later label.

[DartBot]

<img src="https://avatars.githubusercontent.com/u/2049220?v=3" align="left" width="48" height="48"hspace="10"> Comment by sigmundch

---

Removed Polymer-Milestone-Later label.
Added PolymerMilestone-Later label.