Compiler should not request setters for @Viewport bindings

[kegluneq]

This came up originally in #1267 where the Compiler was requesting a setter for if from the template defined on App in this file.

Flagging @yjbanov here since he has more context than I do.

[yjbanov]

To be more precise the compiler should be aware of the fact that in this code:

<template [if]="expression">
  <div></div>
</template>

if is not a setter because <template> is a synthetic element used as the placeholder for @Viewport. It therefore never makes sense to look for a setter for the LHS expression [if].

[naomiblack]

Assigning to Misko to think about the big picture solution to the "if property in Dart" problem. (https://github.com/angular/angular/blob/master/modules/angular2/src/directives/if.js)

[mhevery]

This may not be in issue if #1598

[yjbanov]

@hevery, sorry, not sure I can connect #868 to this issue. Could you elaborate?

[mhevery]

@yjbanov by adding ng-if instead of if (see #1598) this dart problem goes away. (not sure how #868 got pulled into the discussion.)