Fix some egregious bugs in Var.

ppapi/cpp/private/var_private.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef PPAPI_CPP_PRIVATE_VAR_PRIVATE_H_
 #define PPAPI_CPP_PRIVATE_VAR_PRIVATE_H_
 
 #include "ppapi/cpp/var.h"
 
 namespace pp {
@@ skipping 68 matching lines @@
   //   from get, and nothing else should change.
   //
   // Example:
   //   void FooBar(a, b, Var* exception = NULL) {
   //     foo_interface->Bar(a, b, VarPrivate::OutException(exception).get());
   //   }
   class OutException {
    public:
     OutException(Var* v)
         : output_(v),
-          originally_had_exception_(v && v->is_null()) {
+          originally_had_exception_(v && !v->is_undefined()) {
       if (output_) {
         temp_ = output_->pp_var();
       } else {
         temp_.padding = 0;
         temp_.type = PP_VARTYPE_UNDEFINED;
       }
     }
     ~OutException() {
       if (output_ && !originally_had_exception_)
         *output_ = Var(PassRef(), temp_);
@@ skipping 14 matching lines @@
  private:
   // Prevent an arbitrary pointer argument from being implicitly converted to
   // a bool at Var construction. If somebody makes such a mistake, (s)he will
   // get a compilation error.
   VarPrivate(void* non_scriptable_object_pointer);
 };
 
 }  // namespace pp
 
 #endif  // PPAPI_CPP_PRIVATE_VAR_PRIVATE_H_