Make a global enum to differentiate impl & proxy.

ppapi/shared_impl/ppb_video_decoder_shared.cc

Index: ppapi/shared_impl/ppb_video_decoder_shared.cc
diff --git a/ppapi/shared_impl/ppb_video_decoder_shared.cc b/ppapi/shared_impl/ppb_video_decoder_shared.cc
index 39a408882ba45a1b3a5ba398b7ccba21fbd9bee0..2523808a8b9870215a8d1ad6736364642da06f54 100644
--- a/ppapi/shared_impl/ppb_video_decoder_shared.cc
+++ b/ppapi/shared_impl/ppb_video_decoder_shared.cc
@@ -13,14 +13,14 @@
 namespace ppapi {
 
 PPB_VideoDecoder_Shared::PPB_VideoDecoder_Shared(PP_Instance instance)
-    : Resource(instance),
+    : Resource(OBJECT_IS_IMPL, instance),
       graphics_context_(0),
       gles2_impl_(NULL) {
 }
 
 PPB_VideoDecoder_Shared::PPB_VideoDecoder_Shared(
     const HostResource& host_resource)
-    : Resource(host_resource),
+    : Resource(OBJECT_IS_PROXY, host_resource),
       graphics_context_(0),
       gles2_impl_(NULL) {
 }