Troubleshoot Angular Material breakage with "do not write @-bound properties" commit

[jeffbcross]

Troubleshoot Angular Material breakage with 8a1eb16, which was reverted.

This spec is failing: https://github.com/angular/material/blob/786b0ed3652b7460c2c802efa1aa79972bd96f5d/src/components/chips/contact-chips.spec.js#L46

With this error:

Error: [$compile:nonassign] Expression '' used with directive 'mdAutocomplete' is non-assignable!
    http://errors.angularjs.org/1.4.2-build.4088+sha.4da1cc3/$compile/nonassign?p0=&p1=mdAutocomplete
    minErr/<@/material/temp/angular.js:68:12
    initializeDirectiveBindings/</parentSet<@/material/temp/angular.js:8705:1
    parentValueWatch@/material/temp/angular.js:8718:19
    regularInterceptedExpression@/material/temp/angular.js:14227:16
    constantWatch@/material/temp/angular.js:14208:16
    $RootScopeProvider/this.$get</Scope.prototype.$digest@/material/temp/angular.js:15674:34
    $RootScopeProvider/this.$get</Scope.prototype.$apply@/material/temp/angular.js:15950:13
    buildChips/<@/material/src/components/chips/contact-chips.spec.js:98:7
    invoke@/material/temp/angular.js:4452:14
    workFn@/material/temp/angular-mocks.js:2420:11
    angular.mock.inject@/material/temp/angular-mocks.js:2392:30
    buildChips@/material/src/components/chips/contact-chips.spec.js:96:5
    @/material/src/components/chips/contact-chips.spec.js:51:23
    invoke@/material/temp/angular.js:4452:14
    workFn@/material/temp/angular-mocks.js:2420:11

    angular.mock.inject@/material/temp/angular-mocks.js:2391:25
    buildChips@/material/src/components/chips/contact-chips.spec.js:96:5
    @/material/src/components/chips/contact-chips.spec.js:51:23
    invoke@/material/temp/angular.js:4452:14
    workFn@/material/temp/angular-mocks.js:2420:11

    angular.mock.inject@/material/temp/angular-mocks.js:2391:25
    @/material/src/components/chips/contact-chips.spec.js:46:27
    jasmineInterface.describe@/material/node_modules/karma-jasmine/lib/boot.js:59:14
    @/material/src/components/chips/contact-chips.spec.js:45:5
    jasmineInterface.describe@/material/node_modules/karma-jasmine/lib/boot.js:59:14
    @/material/src/components/chips/contact-chips.spec.js:36:3
    jasmineInterface.describe@/material/node_modules/karma-jasmine/lib/boot.js:59:14
    @/material/src/components/chips/contact-chips.spec.js:1:1

CC @ThomasBurleson @caitp