code: public Optional<SanitizedContentKind> getCallContentKind(CallNode node) {
      ImmutableList<TemplateMetadata> templateNodes = getTemplates(node);
      // For per-file compilation, we may not have any of the delegate templates in the compilation
      // unit.
      if (!templateNodes.isEmpty()) {
        return Optional.fromNullable(templateNodes.get(0).getContentKind());
      }
      // The template node may be null if the template is being compiled in isolation.
      return Optional.absent();
    }
docs: Gets the content kind that a call results in. If used with delegate calls, the delegate
  templates must use strict autoescaping. This relies on the fact that all delegate calls must
  have the same kind when using strict autoescaping. This is enforced by CheckDelegatesPass.
  
  @param node The {@link CallBasicNode} or {@link CallDelegateNode}.
  @return The kind of content that the call results in.