message: Add back registry macro used by istio/proxy.  Use absolute naming.
diff: @@ -125,33 +125,41 @@ private:
  std::unordered_map<int64_t, std::unique_ptr<Plugin::ContextBase>> context_map_;
  };
  -#define START_WASM_PLUGIN(_name) \
  - namespace Envoy { \
  - namespace Extensions { \
  - namespace Common { \
  - namespace Wasm { \
  - namespace Null { \
  - namespace Plugin { \
  - namespace _name { \
  - extern ThreadSafeSingleton<Null::NullPluginRegistry> null_plugin_registry_; \
  - extern NullPluginRegistry* context_registry_; \
  +#define NULL_PLUGIN_REGISTRY \
  + extern ThreadSafeSingleton<Envoy::Extensions::Common::Wasm::Null::NullPluginRegistry> \
  + null_plugin_registry_; \
  + extern Envoy::Extensions::Common::Wasm::Null::NullPluginRegistry* context_registry_; \
  struct RegisterContextFactory { \
  - explicit RegisterContextFactory(ContextFactory context_factory, \
  - RootFactory root_factory = nullptr, StringView root_id = "") { \
  + explicit RegisterContextFactory( \
  + Envoy::Extensions::Common::Wasm::Null::Plugin::ContextFactory context_factory, \
  + Envoy::Extensions::Common::Wasm::Null::Plugin::RootFactory root_factory = nullptr, \
  + StringView root_id = "") { \
  if (!context_registry_) { \
  - context_registry_ = new NullPluginRegistry; \
  + context_registry_ = new Envoy::Extensions::Common::Wasm::Null::NullPluginRegistry; \
  } \
  context_registry_->context_factories[std::string(root_id)] = context_factory; \
  context_registry_->root_factories[std::string(root_id)] = root_factory; \
  } \
  - explicit RegisterContextFactory(RootFactory root_factory, StringView root_id = "") { \
  + explicit RegisterContextFactory( \
  + Envoy::Extensions::Common::Wasm::Null::Plugin::RootFactory root_factory, \
  + StringView root_id = "") { \
  if (!context_registry_) { \
  - context_registry_ = new NullPluginRegistry; \
  + context_registry_ = new Envoy::Extensions::Common::Wasm::Null::NullPluginRegistry; \
  } \
  context_registry_->root_factories[std::string(root_id)] = root_factory; \
  } \
  };
  +#define START_WASM_PLUGIN(_name) \
  + namespace Envoy { \
  + namespace Extensions { \
  + namespace Common { \
  + namespace Wasm { \
  + namespace Null { \
  + namespace Plugin { \
  + namespace _name { \
  + NULL_PLUGIN_REGISTRY
  +
  #define END_WASM_PLUGIN \
  } \
  } \
  