message: Switch ResourceHandle to use StringRef when storing container, name, and device strings (NFC).
  These are never created and instead are referencing attributes from an op.
diff: @@ -82,9 +82,9 @@ struct ResourceHandle {
  // Make ResourceHandle hashable.
  friend ::llvm::hash_code hash_value(const ResourceHandle& resource_handle);
  - std::string container;
  - std::string name;
  - std::string device;
  + StringRef container;
  + StringRef name;
  + StringRef device;
  Operation* op = nullptr;
  };
  