Support for negative numbers in computed bindings

@@ -221,6 +221,7 @@
           a.literal = true;
           break;
         case '#':
+        case '-':
           a.value = Number(arg);
           a.literal = true;
           break;

@@ -11,6 +11,7 @@
       computed-inline2="{{computeInline(value, add,divide)}}"
       computedattribute$="{{computeInline(value, add,divide)}}"
       neg-computed-inline="{{!computeInline(value,add,divide)}}"
+      computed-negative-number="{{computeNegativeNumber(-1)}}"
       style$="{{boundStyle}}"
       data-id$="{{dataSetId}}"
       custom-event-value="{{customEventValue::custom}}"
@@ -232,6 +233,9 @@
       },
       computeFromNoArgs: function() {
         return 'no args!';
+      },
+      computeNegativeNumber: function (num) {
+        return num;
       }
     });
   </script>

@@ -262,6 +262,10 @@
     assert.equal(el.observerCounts.customEventObjectValueChanged, 1, 'custom bound path observer not called');
   });
 
+  test('computed property with negative number', function() {
+    assert.equal(el.$.boundChild.computedNegativeNumber, -1);
+  });
+
 });
 
 </script>
@@ -684,14 +688,14 @@
 
 <script>
   suite('binding corner cases', function() {
-    
+
     // IE can create adjacent text nodes that split bindings; this test
     // ensures the code that addresses this is functional
     test('text binding after entity', function() {
       var el = document.createElement('x-entity-and-binding');
       assert.equal(el.$.binding.textContent, 'binding');
     });
-    
+
   });
 </script>