Make sure that parts of a date are returned as ints.

lib/compiler/implementation/ssa/codegen.dart

Index: lib/compiler/implementation/ssa/codegen.dart
diff --git a/lib/compiler/implementation/ssa/codegen.dart b/lib/compiler/implementation/ssa/codegen.dart
index 98a7c72ccf61d68f50a04916fd76a659f32ff031..d8cda34819f032deac654b695f644fdd9f52c831 100644
--- a/lib/compiler/implementation/ssa/codegen.dart
+++ b/lib/compiler/implementation/ssa/codegen.dart
@@ -2157,7 +2157,7 @@ abstract class SsaCodeGenerator implements HVisitor, HBlockInformationVisitor {
     js.Expression left = pop();
     use(input);
     js.Expression right = pop();
-    // TODO(4984): Deal with infinity.
+    // TODO(4984): Deal with infinity and -0.0.
     push(new js.LiteralExpression.withData('Math.floor(#) === #',
                                            <js.Expression>[left, right]));
   }