Accept no-arg computed fns as static. Fixes #1516.

src/standard/effectBuilder.html

@@ -169,20 +169,26 @@
       var m = expression.match(/(\w*)\((.*)\)/);
       if (m) {
         // replace escaped commas with comma entity, split on un-escaped commas
-        var args = m[2].replace(/\\,/g, ',').split(',');
-        return this._parseArgs(args, { method: m[1], static: true });
+        var sig = { method: m[1], static: true };
+        if (m[2].trim()) {
+          var args = m[2].replace(/\\,/g, ',').split(',');
+          return this._parseArgs(args, sig);
+        } else {
+          sig.args = Polymer.nar;
+          return sig;
+        }
       }
     },
 
-    _parseArgs: function(argList, effect) {
-      effect.args = argList.map(function(rawArg) {
+    _parseArgs: function(argList, sig) {
+      sig.args = argList.map(function(rawArg) {
         var arg = this._parseArg(rawArg);
         if (!arg.literal) {
-          effect.static = false;
+          sig.static = false;
         }
         return arg;
       }, this);
-      return effect;
+      return sig;
     },
 
     _parseArg: function(rawArg) {

test/unit/bind-elements.html

@@ -18,6 +18,7 @@
     computed-from-pure-literals='{{computeFromLiterals( 3, "foo")}}'
     computed-from-tricky-literals="{{computeFromTrickyLiterals(3, 'tricky\,\'zot\'')}}"
     computed-from-tricky-literals2='{{computeFromTrickyLiterals(3,"tricky\,\'zot\'" )}}'
+    computed-from-no-args="{{computeFromNoArgs( )}}"
     >
     Test
     </div>
@@ -198,6 +199,9 @@
     },
     computeFromTrickyLiterals: function(a, b) {
       return a + b;
+    },
+    computeFromNoArgs: function() {
+      return 'no args!';
     }
   });
 </script>

test/unit/bind.html

@@ -146,6 +146,10 @@
     assert.equal(el.$.computedContent.textContent, '3tricky,\'zot\'', 'Wrong textContent from tricky literal arg computation');
   });
 
+  test('computed annotation with no args', function() {
+    assert.equal(el.$.boundChild.computedFromNoArgs, 'no args!', 'Wrong content when computed has no args');
+  });
+
   test('no read-only observer called with assignment', function() {
     el.readolyvalue = 46;
     assert.equal(el.observerCounts.readonlyvalueChanged, 0, 'observer should not be called for readOnly prop assignment');