Create a VarPrivate interface to contain the scripting helper functions of Var.

ppapi/proxy/serialized_var.cc

Index: ppapi/proxy/serialized_var.cc
===================================================================
--- ppapi/proxy/serialized_var.cc	(revision 80958)
+++ ppapi/proxy/serialized_var.cc	(working copy)
@@ -147,6 +147,11 @@
     case PP_VARTYPE_OBJECT:
       m->WriteInt64(var_.value.as_id);
       break;
+    case PP_VARTYPE_ARRAY:
+    case PP_VARTYPE_DICTIONARY:
+      // TODO(brettw) when these are supported, implement this.
+      NOTIMPLEMENTED();
+      break;
   }
 }
 
@@ -196,6 +201,11 @@
     case PP_VARTYPE_OBJECT:
       success = m->ReadInt64(iter, &var_.value.as_id);
       break;
+    case PP_VARTYPE_ARRAY:
+    case PP_VARTYPE_DICTIONARY:
+      // TODO(brettw) when these types are supported, implement this.
+      NOTIMPLEMENTED();
+      break;
     default:
       // Leave success as false.
       break;