Restore original function as well, since the RenderMan plugin uses th…

…at API

pxr/imaging/hd/materialSchema.cpp

@@ -40,6 +40,20 @@ HdMaterialSchema::GetMaterialNetwork()
                 HdMaterialSchemaTokens->universalRenderContext));
 }
 
+HdMaterialNetworkSchema
+HdMaterialSchema::GetMaterialNetwork(TfToken const &context)
+{
+    if (auto b = _GetTypedDataSource<HdContainerDataSource>(context)) {
+        return HdMaterialNetworkSchema(b);
+    }
+
+    // If we can't find the context-specific binding, return the fallback.
+    return
+        HdMaterialNetworkSchema(
+            _GetTypedDataSource<HdContainerDataSource>(
+                HdMaterialSchemaTokens->universalRenderContext));
+}
+
 HdMaterialNetworkSchema
 HdMaterialSchema::GetMaterialNetwork(TfTokenVector const &contexts)
 {

pxr/imaging/hd/materialSchema.h

@@ -68,6 +68,9 @@ class HdMaterialSchema : public HdSchema
     HD_API
     HdMaterialNetworkSchema GetMaterialNetwork();
 
+    HD_API
+    HdMaterialNetworkSchema GetMaterialNetwork(TfToken const &context);
+
     HD_API
     HdMaterialNetworkSchema GetMaterialNetwork(TfTokenVector const &contexts);