Proper implementation

Replace ad hoc hack with a proper implementation.

src/standard/annotations.html

@@ -147,11 +147,8 @@ TODO(sjmiles): this module should produce either syntactic metadata
             if (!p.literal) {
               var signature = this._parseMethod(p.value);
               if (signature) {
-                var method = signature.method;
-                if (this.properties[method]) {
-                  var args = signature.args || [];
-                  args.push(this._parseArg(method));
-                  signature.args = args;
+                if (this.properties[signature.method]) {
+                  signature.dynamicFn = true;
                   signature.static = false;
                 }
                 p.signature = signature;

src/standard/effectBuilder.html

@@ -171,6 +171,14 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
               arg);
           }
         }
+        if (sig.dynamicFn) {
+          // trigger=null is sufficient as long as we don't allow paths to be
+          // used. If we change our mind, we must first implement this in the
+          // effects anyway where we basically do a `fn = this[methodName]` at
+          // the moment.
+          this.__addAnnotatedComputationEffect(
+              sig.method, index, note, part, null);
+        }
       }
     },
 

test/unit/bind.html

@@ -285,7 +285,7 @@ suite('single-element binding effects', function() {
 
 <script>
 
-suite('computed properties', function() {
+suite('computed bindings with dynamic functions', function() {
 
   var el;
 
@@ -297,7 +297,7 @@ suite('computed properties', function() {
     document.body.removeChild(el);
   });
 
-  test('x', function() {
+  test('annotated computation with dynamic function', function() {
     el = document.createElement('x-bind-computed-property');
     document.body.appendChild(el);