Initial support for computed properties

Initial support for computed properties

R=sjmiles@google.com, sjmiles
BUG=

Committed: https://github.com/Polymer/polymer-dev/commit/27b6f83

[sjmiles, 2014-06-03 19:44:06]

A few minor nits and an overall question in the code notes.

Otherwise, LGTM.

https://codereview.appspot.com/103020045/diff/20001/src/declaration/propertie...
File src/declaration/properties.js (right):

https://codereview.appspot.com/103020045/diff/20001/src/declaration/propertie...
src/declaration/properties.js:60: if (prototype.computed) {
This object-busting optimization mattered in micro-benchmarks, but had no effect
in real-world scenarios. Do we still want/need this code (the whole concept, not
just the new part)?

https://codereview.appspot.com/103020045/diff/20001/src/instance/properties.js
File src/instance/properties.js (right):

https://codereview.appspot.com/103020045/diff/20001/src/instance/properties.j...
src/instance/properties.js:100: if (!this._computedNames)
This is arbitrary, but our style guide requires braces around all blocks, so 
if (expr) { statement }
not
if (expr) statement

https://codereview.appspot.com/103020045/diff/20001/src/instance/properties.j...
src/instance/properties.js:107: if (!expression)
We generally prefer 
if (expression) { task } 
rather than
if (!expression) continue;

[rafaelw, 2014-06-03 20:15:25]

https://codereview.appspot.com/103020045/diff/20001/src/declaration/propertie...
File src/declaration/properties.js (right):

https://codereview.appspot.com/103020045/diff/20001/src/declaration/propertie...
src/declaration/properties.js:60: if (prototype.computed) {
keeping for now. 

On 2014/06/03 19:44:05, sjmiles wrote:
> This object-busting optimization mattered in micro-benchmarks, but had no
effect
> in real-world scenarios. Do we still want/need this code (the whole concept,
not
> just the new part)?

https://codereview.appspot.com/103020045/diff/20001/src/instance/properties.js
File src/instance/properties.js (right):

https://codereview.appspot.com/103020045/diff/20001/src/instance/properties.j...
src/instance/properties.js:100: if (!this._computedNames)
On 2014/06/03 19:44:05, sjmiles wrote:
> This is arbitrary, but our style guide requires braces around all blocks, so 
> if (expr) { statement }
> not
> if (expr) statement

Done.

https://codereview.appspot.com/103020045/diff/20001/src/instance/properties.j...
src/instance/properties.js:107: if (!expression)
done. FWIW, google/chrome team style is to prefer early return syntax.

On 2014/06/03 19:44:06, sjmiles wrote:
> We generally prefer 
> if (expression) { task } 
> rather than
> if (!expression) continue;

[rafaelw, 2014-06-03 20:20:28]

Committed patchset #3 manually as r27b6f83 (presubmit successful).