Ensure libraries always have at least one top-level class and therefore at least one script.

runtime/vm/parser.cc

Index: runtime/vm/parser.cc
diff --git a/runtime/vm/parser.cc b/runtime/vm/parser.cc
index 3dc9370481d463c84d6f8361e2968c63e84f7bcb..aa8bc9796e83ee11e29544e19250c95c56dd320d 100644
--- a/runtime/vm/parser.cc
+++ b/runtime/vm/parser.cc
@@ -5970,16 +5970,14 @@ void Parser::ParseTopLevel() {
       }
     }
   }
-  if ((top_level.fields.Length() > 0) || (top_level.functions.Length() > 0)) {
-    toplevel_class.AddFields(top_level.fields);
 
-    const Array& array = Array::Handle(Z,
-                                       Array::MakeArray(top_level.functions));
-    toplevel_class.SetFunctions(array);
+  toplevel_class.AddFields(top_level.fields);
 
-    library_.AddAnonymousClass(toplevel_class);
-    pending_classes.Add(toplevel_class, Heap::kOld);
-  }
+  const Array& array = Array::Handle(Z, Array::MakeArray(top_level.functions));
+  toplevel_class.SetFunctions(array);
+
+  library_.AddAnonymousClass(toplevel_class);

[hausner, 2015/05/19 05:43:03]

A library with 100 part files will now have 100 top-level classes, right?
Instead of creating a TL class unconditionally, you could change the old code
to:

if ((library_ has no top-level classes) || 
    (top_level.fields.Length() > 0) || (top_level.functions.Length() > 0)) {
....

[rmacnak, 2015/05/19 15:57:41]

Done.

+  pending_classes.Add(toplevel_class, Heap::kOld);
 }