Start checking inputs to dart api functions.

runtime/vm/object.h

Index: runtime/vm/object.h
===================================================================
--- runtime/vm/object.h	(revision 1707)
+++ runtime/vm/object.h	(working copy)
@@ -1532,6 +1532,9 @@
 
   RawString* url() const { return raw_ptr()->url_; }
   RawString* private_key() const { return raw_ptr()->private_key_; }
+  bool NotLoaded() const {

[siva, 2011/11/21 18:24:59]

The name NotLoaded() sounds like a negation of Loaded() but it is not quite a
pure negation.
How about NoLoadsIssued() or LoadNotIssued() or NoLoadsAttemptedYet()

[turnidge, 2011/11/21 18:52:16]

Going with LoadNotStarted for now.

+    return raw_ptr()->load_state_ == RawLibrary::kAllocated;
+  }
   bool LoadInProgress() const {
     return raw_ptr()->load_state_ == RawLibrary::kLoadInProgress;
   }