Handle the case where the v8 scriptable object has a property defined with value undefined.

ppapi/tests/blink_deprecated_test_plugin.cc

Index: ppapi/tests/blink_deprecated_test_plugin.cc
diff --git a/ppapi/tests/blink_deprecated_test_plugin.cc b/ppapi/tests/blink_deprecated_test_plugin.cc
index 064cc90f2dafaa013b16919825c0881a74d1943c..cda8f207469dc46e5c064e61df4ee0e2e4403651 100644
--- a/ppapi/tests/blink_deprecated_test_plugin.cc
+++ b/ppapi/tests/blink_deprecated_test_plugin.cc
@@ -49,6 +49,8 @@
 // Properties:
 // * plugin.testObject (read-only): a TestObject instance (see below).
 //
+// * plugin.testGetUndefined (read-only): returns undefined.
+//
 //
 // TestObject exposes the following interface:
 // Properties:
@@ -199,6 +201,9 @@ class InstanceSO : public ScriptableBase {
     properties_.insert(std::make_pair(
         "testObject", base::Bind(&InstanceSO::TestObjectAccessor,
                                  base::Unretained(this))));
+    properties_.insert(std::make_pair(
+        "testGetUndefined", base::Bind(&InstanceSO::TestGetUndefinedAccessor,
+                                       base::Unretained(this))));
   }
   ~InstanceSO() override {}
 
@@ -274,6 +279,12 @@ class InstanceSO : public ScriptableBase {
     *var = test_object_;
   }
 
+  void TestGetUndefinedAccessor(bool set, pp::Var* var) {
+    if (set)
+      return;
+    *var = pp::Var();
+  }
+
   pp::VarPrivate test_object_;
   pp::Var remembered_;
 };