Add PPB_VarDictionary_Dev support - part 1.

ppapi/shared_impl/scoped_pp_var.cc

Index: ppapi/shared_impl/scoped_pp_var.cc
diff --git a/ppapi/shared_impl/scoped_pp_var.cc b/ppapi/shared_impl/scoped_pp_var.cc
index fcd6806ed063866923a3ca3d4559f8cb0054c943..3ae13b0445a940185424bb4fd4fa1c3be2d7688e 100644
--- a/ppapi/shared_impl/scoped_pp_var.cc
+++ b/ppapi/shared_impl/scoped_pp_var.cc
@@ -47,4 +47,10 @@ ScopedPPVar& ScopedPPVar::operator=(const PP_Var& v) {
   return *this;
 }
 
+PP_Var ScopedPPVar::Release() {
+  PP_Var result = var_;
+  var_ = PP_MakeUndefined();
+  return result;
+}
+
 }  // namespace ppapi