Fix bug where constants were not correctly canonicalized.

lib/compiler/implementation/emitter.dart

Index: lib/compiler/implementation/emitter.dart
diff --git a/lib/compiler/implementation/emitter.dart b/lib/compiler/implementation/emitter.dart
index c7fb5b0ee3bd5c4090cab188afa99a368d746fd6..8dc5653230663462caa3cb2d47d3e2cdb9978609 100644
--- a/lib/compiler/implementation/emitter.dart
+++ b/lib/compiler/implementation/emitter.dart
@@ -147,8 +147,9 @@ function(child, parent) {
               // down to the native method.
               indexOfLastOptionalArgumentInParameters = count;
             }
-            argumentsBuffer[count] =
-                handler.writeJsCode(new StringBuffer(), value).toString();
+            StringBuffer argumentBuffer = new StringBuffer();
+            handler.writeCanonicalizedJsCode(argumentBuffer, value);
+            argumentsBuffer[count] = argumentBuffer.toString();
           }
         }
       }