[clike mode] Style Dart class names as variable-2

mode/dart/dart.js

@@ -78,6 +78,15 @@
         if (!stream.eat("*")) return false
         state.tokenize = tokenNestedComment(1)
         return state.tokenize(stream, state)
+      },
+      token: function(stream, _, style) {
+        if (style == "variable") {
+          // Assume uppercase symbols are classes using variable-2
+          var isUpper = RegExp('^[_$]*[A-Z][a-zA-Z0-9_$]*$','g');
+          if (isUpper.test(stream.current())) {
+            return 'variable-2';
+          }
+        }
       }
     }
   });