Remove the old type system for proxied resources. These were no longer being used.

ppapi/proxy/plugin_resource.cc

Index: ppapi/proxy/plugin_resource.cc
diff --git a/ppapi/proxy/plugin_resource.cc b/ppapi/proxy/plugin_resource.cc
index 186ff7453af1c78d195ecc1d294609b6ba35d9ef..67a47f445e0d7d57b4db8b79b3d47f5a23ad7b94 100644
--- a/ppapi/proxy/plugin_resource.cc
+++ b/ppapi/proxy/plugin_resource.cc
@@ -15,11 +15,6 @@ PluginResource::PluginResource(const HostResource& resource)
 PluginResource::~PluginResource() {
 }
 
-#define DEFINE_TYPE_GETTER(RESOURCE)                    \
-  RESOURCE* PluginResource::As##RESOURCE() { return NULL; }
-FOR_ALL_PLUGIN_RESOURCES(DEFINE_TYPE_GETTER)
-#undef DEFINE_TYPE_GETTER
-
 PluginDispatcher* PluginResource::GetDispatcher() {
   PluginDispatcher* disp = PluginDispatcher::GetForInstance(instance());
   CHECK(disp);